Improving all side of app

TODO.md

@@ -0,0 +1,28 @@
+# TODO
+
+- [ ] Implement git style versioning for: synthetic variable, panels, control logic
+- [ ] Implement configuration manager:
+  - configuration is a set of signals (that can be organized in group and subgroup) that are used to configure a system or a sub system
+  - with configuration manager user should be able to:
+    - Define and manage configuration sets: delete (keep server side copy of deleted config), create (specifying default to parameters, mandatory, optional etc), edit (with versioning git style) and compare set
+      - user can fork an existing config instance to create a new one
+      - user can compare two instances: show unified diff or side by side diff
+      - etc...
+    - Create, delete (keep server cache), edit (git style versioning) and compare configuration instances: meaning set actual value to a configuration set
+      - user can fork an existing config instance to create a new one
+      - user can compare two instances: show unified diff or side by side diff
+      - etc...
+- [ ] Implement admin pane: create / manage groups, set users permits, manage auditors etc
+- [ ] Implement new datasources:
+  - [ ] modbus tcp
+  - [ ] scpi tcp
+- [ ] Improve UX:
+  - [ ] Synthetic editor:
+    - color code the node link by type
+    - hover on a block in error should show the reason
+    - add proper array functionality
+    - add shortcut to add Signals (S) and nodes (N) with HUD
+  - [ ] Panels:
+    - in view mode the widgets should have no border/bg but blend with background
+    - add widgets such
+- [ ] Implement proper distributed server side nodes to balance load and have redundancy (if a node is not available anymore all its clients migrate seamelessly to another)

cmd/uopi/main.go

@@ -9,14 +9,18 @@ import (
 	"log/slog"
 	"os"
 	"os/signal"
+	"os/user"
+	"path/filepath"
 	"syscall"
 
 	"github.com/uopi/uopi/internal/access"
+	"github.com/uopi/uopi/internal/audit"
 	"github.com/uopi/uopi/internal/broker"
 	"github.com/uopi/uopi/internal/config"
 	"github.com/uopi/uopi/internal/controllogic"
 	"github.com/uopi/uopi/internal/datasource/epics"
 	"github.com/uopi/uopi/internal/datasource/pva"
+	"github.com/uopi/uopi/internal/datasource/servervar"
 	"github.com/uopi/uopi/internal/datasource/stub"
 	"github.com/uopi/uopi/internal/datasource/synthetic"
 	"github.com/uopi/uopi/internal/panelacl"
@@ -41,6 +45,16 @@ func main() {
 		os.Exit(1)
 	}
 
+	// In an unproxied/local deployment (no trusted_user_header) without an explicit
+	// default_user, attribute actions to the OS user running the process so the UI
+	// and audit log show a real identity instead of anonymous.
+	if cfg.Server.TrustedUserHeader == "" && cfg.Server.DefaultUser == "" {
+		if u, err := user.Current(); err == nil && u.Username != "" {
+			cfg.Server.DefaultUser = u.Username
+			log.Info("no default_user configured; defaulting to OS user", "user", u.Username)
+		}
+	}
+
 	if err := os.MkdirAll(cfg.Server.StorageDir, 0o755); err != nil {
 		log.Error("failed to create storage dir", "dir", cfg.Server.StorageDir, "err", err)
 		os.Exit(1)
@@ -122,6 +136,15 @@ func main() {
 		}
 	}
 
+	// Server variables: a small persistent key/value source ("srv") that the
+	// control-logic engine writes (e.g. sequence state) and panels can read.
+	srvVars, err := servervar.New(cfg.Server.StorageDir)
+	if err != nil {
+		log.Error("server variables init", "err", err)
+		os.Exit(1)
+	}
+	brk.Register(srvVars)
+
 	// Build the global access policy from config: every user is trusted with
 	// full write access unless downgraded by the blacklist; groups are named
 	// sets of users referenced by per-panel sharing.
@@ -133,7 +156,26 @@ func main() {
 	for _, g := range cfg.Groups {
 		groups[g.Name] = g.Members
 	}
-	policy := access.New(cfg.Server.DefaultUser, blacklist, groups, cfg.Server.LogicEditors)
+	policy := access.New(cfg.Server.DefaultUser, blacklist, groups, cfg.Server.LogicEditors, cfg.Audit.Readers)
+
+	// Audit log: when enabled, every system-affecting action (user/automated
+	// signal writes, interface and control-logic mutations) is recorded to SQLite.
+	// When disabled a no-op recorder is used so call sites need no guards.
+	recorder := audit.Nop()
+	if cfg.Audit.Enabled {
+		dbPath := cfg.Audit.DBPath
+		if dbPath == "" {
+			dbPath = filepath.Join(cfg.Server.StorageDir, "audit.db")
+		}
+		r, err := audit.NewSQLite(dbPath, log)
+		if err != nil {
+			log.Error("failed to open audit log", "path", dbPath, "err", err)
+			os.Exit(1)
+		}
+		defer r.Close()
+		recorder = r
+		log.Info("audit log enabled", "path", dbPath)
+	}
 
 	// Server-side control logic: flow graphs that run continuously under the root
 	// context, independent of any panel. The store is loaded from disk and the
@@ -143,10 +185,16 @@ func main() {
 		log.Error("failed to open control logic store", "err", err)
 		os.Exit(1)
 	}
-	ctrlEngine := controllogic.NewEngine(ctx, brk, ctrlStore, log)
+	ctrlEngine := controllogic.NewEngine(ctx, brk, ctrlStore, recorder, log)
+
+	// Dialog hub: control-logic action.dialog nodes push notifications/inputs to
+	// connected clients (filtered by user/group) and route input responses back
+	// to server variables. Installed before Reload so running graphs can emit.
+	dialogs := server.NewDialogHub(brk, policy, recorder, log)
+	ctrlEngine.SetNotifier(dialogs)
 	ctrlEngine.Reload()
 
-	srv := server.New(cfg.Server.Listen, webFS, brk, synthDS, store, policy, aclStore, ctrlStore, ctrlEngine, cfg.Datasource.EPICS.ChannelFinderURL, cfg.Datasource.EPICS.ArchiveURL, cfg.Server.TrustedUserHeader, log)
+	srv := server.New(cfg.Server.Listen, webFS, brk, synthDS, store, policy, aclStore, ctrlStore, ctrlEngine, dialogs, recorder, cfg.Datasource.EPICS.ChannelFinderURL, cfg.Datasource.EPICS.ArchiveURL, cfg.Server.TrustedUserHeader, log)
 
 	if err := srv.Start(ctx); err != nil {
 		fmt.Fprintf(os.Stderr, "server error: %v\n", err)

go.mod

@@ -9,4 +9,16 @@ require (
 	github.com/yuin/gopher-lua v1.1.2
 )
 
-require golang.org/x/sys v0.0.0-20220715151400-c0bba94af5f8 // indirect
+require (
+	github.com/dustin/go-humanize v1.0.1 // indirect
+	github.com/google/uuid v1.6.0 // indirect
+	github.com/mattn/go-isatty v0.0.20 // indirect
+	github.com/ncruces/go-strftime v0.1.9 // indirect
+	github.com/remyoudompheng/bigfft v0.0.0-20230129092748-24d4a6f8daec // indirect
+	golang.org/x/exp v0.0.0-20250620022241-b7579e27df2b // indirect
+	golang.org/x/sys v0.36.0 // indirect
+	modernc.org/libc v1.66.10 // indirect
+	modernc.org/mathutil v1.7.1 // indirect
+	modernc.org/memory v1.11.0 // indirect
+	modernc.org/sqlite v1.42.2 // indirect
+)

go.sum

@@ -2,9 +2,32 @@ github.com/BurntSushi/toml v1.6.0 h1:dRaEfpa2VI55EwlIW72hMRHdWouJeRF7TPYhI+AUQjk
 github.com/BurntSushi/toml v1.6.0/go.mod h1:ukJfTF/6rtPPRCnwkur4qwRxa8vTRFBF0uk2lLoLwho=
 github.com/coder/websocket v1.8.14 h1:9L0p0iKiNOibykf283eHkKUHHrpG7f65OE3BhhO7v9g=
 github.com/coder/websocket v1.8.14/go.mod h1:NX3SzP+inril6yawo5CQXx8+fk145lPDC6pumgx0mVg=
+github.com/dustin/go-humanize v1.0.1 h1:GzkhY7T5VNhEkwH0PVJgjz+fX1rhBrR7pRT3mDkpeCY=
+github.com/dustin/go-humanize v1.0.1/go.mod h1:Mu1zIs6XwVuF/gI1OepvI0qD18qycQx+mFykh5fBlto=
 github.com/evanw/esbuild v0.28.0 h1:V96ghtc5p5JnNUQIUsc5H3kr+AcFcMqOJll2ZmJW6Lo=
 github.com/evanw/esbuild v0.28.0/go.mod h1:D2vIQZqV/vIf/VRHtViaUtViZmG7o+kKmlBfVQuRi48=
+github.com/google/uuid v1.6.0 h1:NIvaJDMOsjHA8n1jAhLSgzrAzy1Hgr+hNrb57e+94F0=
+github.com/google/uuid v1.6.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
+github.com/mattn/go-isatty v0.0.20 h1:xfD0iDuEKnDkl03q4limB+vH+GxLEtL/jb4xVJSWWEY=
+github.com/mattn/go-isatty v0.0.20/go.mod h1:W+V8PltTTMOvKvAeJH7IuucS94S2C6jfK/D7dTCTo3Y=
+github.com/ncruces/go-strftime v0.1.9 h1:bY0MQC28UADQmHmaF5dgpLmImcShSi2kHU9XLdhx/f4=
+github.com/ncruces/go-strftime v0.1.9/go.mod h1:Fwc5htZGVVkseilnfgOVb9mKy6w1naJmn9CehxcKcls=
+github.com/remyoudompheng/bigfft v0.0.0-20230129092748-24d4a6f8daec h1:W09IVJc94icq4NjY3clb7Lk8O1qJ8BdBEF8z0ibU0rE=
+github.com/remyoudompheng/bigfft v0.0.0-20230129092748-24d4a6f8daec/go.mod h1:qqbHyh8v60DhA7CoWK5oRCqLrMHRGoxYCSS9EjAz6Eo=
 github.com/yuin/gopher-lua v1.1.2 h1:yF/FjE3hD65tBbt0VXLE13HWS9h34fdzJmrWRXwobGA=
 github.com/yuin/gopher-lua v1.1.2/go.mod h1:7aRmXIWl37SqRf0koeyylBEzJ+aPt8A+mmkQ4f1ntR8=
+golang.org/x/exp v0.0.0-20250620022241-b7579e27df2b h1:M2rDM6z3Fhozi9O7NWsxAkg/yqS/lQJ6PmkyIV3YP+o=
+golang.org/x/exp v0.0.0-20250620022241-b7579e27df2b/go.mod h1:3//PLf8L/X+8b4vuAfHzxeRUl04Adcb341+IGKfnqS8=
 golang.org/x/sys v0.0.0-20220715151400-c0bba94af5f8 h1:0A+M6Uqn+Eje4kHMK80dtF3JCXC4ykBgQG4Fe06QRhQ=
 golang.org/x/sys v0.0.0-20220715151400-c0bba94af5f8/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.36.0 h1:KVRy2GtZBrk1cBYA7MKu5bEZFxQk4NIDV6RLVcC8o0k=
+golang.org/x/sys v0.36.0/go.mod h1:OgkHotnGiDImocRcuBABYBEXf8A9a87e/uXjp9XT3ks=
+modernc.org/libc v1.66.10 h1:yZkb3YeLx4oynyR+iUsXsybsX4Ubx7MQlSYEw4yj59A=
+modernc.org/libc v1.66.10/go.mod h1:8vGSEwvoUoltr4dlywvHqjtAqHBaw0j1jI7iFBTAr2I=
+modernc.org/mathutil v1.7.1 h1:GCZVGXdaN8gTqB1Mf/usp1Y/hSqgI2vAGGP4jZMCxOU=
+modernc.org/mathutil v1.7.1/go.mod h1:4p5IwJITfppl0G4sUEDtCr4DthTaT47/N3aT6MhfgJg=
+modernc.org/memory v1.11.0 h1:o4QC8aMQzmcwCK3t3Ux/ZHmwFPzE6hf2Y5LbkRs+hbI=
+modernc.org/memory v1.11.0/go.mod h1:/JP4VbVC+K5sU2wZi9bHoq2MAkCnrt2r98UGeSK7Mjw=
+modernc.org/sqlite v1.42.2 h1:7hkZUNJvJFN2PgfUdjni9Kbvd4ef4mNLOu0B9FGxM74=
+modernc.org/sqlite v1.42.2/go.mod h1:+VkC6v3pLOAE0A0uVucQEcbVW0I5nHCeDaBf+DpsQT8=

internal/access/access.go

@@ -61,18 +61,20 @@ type Policy struct {
 	userGroups   map[string][]string // user → groups they belong to
 	groupNames   []string            // all configured group names (sorted)
 	logicEditors map[string]bool     // users + group names allowed to edit logic
+	auditReaders map[string]bool     // users + group names allowed to view the audit log
 }
 
 // New builds a Policy. blacklist maps a username to a config level string;
 // groups maps a group name to its member usernames. logicEditors optionally
 // restricts who may edit panel/control logic (usernames or group names); empty
 // means no restriction.
-func New(defaultUser string, blacklist map[string]string, groups map[string][]string, logicEditors []string) *Policy {
+func New(defaultUser string, blacklist map[string]string, groups map[string][]string, logicEditors, auditReaders []string) *Policy {
 	p := &Policy{
 		defaultUser:  strings.TrimSpace(defaultUser),
 		blacklist:    make(map[string]Level),
 		userGroups:   make(map[string][]string),
 		logicEditors: make(map[string]bool),
+		auditReaders: make(map[string]bool),
 	}
 	for _, e := range logicEditors {
 		e = strings.TrimSpace(e)
@@ -80,6 +82,12 @@ func New(defaultUser string, blacklist map[string]string, groups map[string][]st
 			p.logicEditors[e] = true
 		}
 	}
+	for _, e := range auditReaders {
+		e = strings.TrimSpace(e)
+		if e != "" {
+			p.auditReaders[e] = true
+		}
+	}
 	for user, lvl := range blacklist {
 		u := strings.TrimSpace(user)
 		if u == "" {
@@ -165,6 +173,29 @@ func (p *Policy) CanEditLogic(user string) bool {
 	return false
 }
 
+// CanViewAudit reports whether a user may view the audit log. When no reader
+// allowlist is configured everyone with read access qualifies; otherwise the
+// user (or one of their groups) must be listed. Anonymous/trusted-LAN callers
+// (user=="") are always permitted.
+func (p *Policy) CanViewAudit(user string) bool {
+	user = strings.TrimSpace(user)
+	if user == "" {
+		return true
+	}
+	if len(p.auditReaders) == 0 {
+		return true
+	}
+	if p.auditReaders[user] {
+		return true
+	}
+	for _, g := range p.userGroups[user] {
+		if p.auditReaders[g] {
+			return true
+		}
+	}
+	return false
+}
+
 // GroupsOf returns a copy of the groups a user belongs to.
 func (p *Policy) GroupsOf(user string) []string {
 	src := p.userGroups[strings.TrimSpace(user)]

internal/access/access_test.go

@@ -6,7 +6,7 @@ func TestCanEditLogic(t *testing.T) {
 	groups := map[string][]string{"ops": {"carol"}}
 
 	// No allowlist configured: everyone with write access may edit logic.
-	open := New("", nil, groups, nil)
+	open := New("", nil, groups, nil, nil)
 	for _, u := range []string{"", "alice", "carol"} {
 		if !open.CanEditLogic(u) {
 			t.Errorf("unrestricted: CanEditLogic(%q) = false, want true", u)
@@ -17,7 +17,7 @@ func TestCanEditLogic(t *testing.T) {
 	}
 
 	// Allowlist by username and by group name.
-	p := New("", nil, groups, []string{"alice", "ops"})
+	p := New("", nil, groups, []string{"alice", "ops"}, nil)
 	if !p.LogicRestricted() {
 		t.Error("LogicRestricted() = false with allowlist set")
 	}

internal/api/api.go

@@ -8,12 +8,15 @@ import (
 	"errors"
 	"io"
 	"log/slog"
+	"net"
 	"net/http"
 	"net/url"
 	"strconv"
 	"strings"
+	"time"
 
 	"github.com/uopi/uopi/internal/access"
+	"github.com/uopi/uopi/internal/audit"
 	"github.com/uopi/uopi/internal/broker"
 	"github.com/uopi/uopi/internal/controllogic"
 	"github.com/uopi/uopi/internal/datasource"
@@ -31,13 +34,18 @@ type Handler struct {
 	acl              *panelacl.Store
 	ctrlLogic        *controllogic.Store
 	ctrlEngine       *controllogic.Engine
-	channelFinderURL string // empty if not configured
+	audit            audit.Recorder // never nil; audit.Nop when disabled
-	archiverURL      string // empty if not configured
+	channelFinderURL string         // empty if not configured
+	archiverURL      string         // empty if not configured
 	log              *slog.Logger
 }
 
 // New creates an API Handler. synth may be nil if the synthetic DS is disabled.
-func New(b *broker.Broker, synth *synthetic.Synthetic, store *storage.Store, policy *access.Policy, acl *panelacl.Store, ctrlLogic *controllogic.Store, ctrlEngine *controllogic.Engine, channelFinderURL, archiverURL string, log *slog.Logger) *Handler {
+// rec records system-affecting mutations; pass audit.Nop() to disable auditing.
+func New(b *broker.Broker, synth *synthetic.Synthetic, store *storage.Store, policy *access.Policy, acl *panelacl.Store, ctrlLogic *controllogic.Store, ctrlEngine *controllogic.Engine, rec audit.Recorder, channelFinderURL, archiverURL string, log *slog.Logger) *Handler {
+	if rec == nil {
+		rec = audit.Nop()
+	}
 	return &Handler{
 		broker:           b,
 		synthetic:        synth,
@@ -46,6 +54,7 @@ func New(b *broker.Broker, synth *synthetic.Synthetic, store *storage.Store, pol
 		acl:              acl,
 		ctrlLogic:        ctrlLogic,
 		ctrlEngine:       ctrlEngine,
+		audit:            rec,
 		channelFinderURL: channelFinderURL,
 		archiverURL:      archiverURL,
 		log:              log,
@@ -56,6 +65,7 @@ func New(b *broker.Broker, synth *synthetic.Synthetic, store *storage.Store, pol
 // Requires Go 1.22+ for method+path routing.
 func (h *Handler) Register(mux *http.ServeMux, prefix string) {
 	mux.HandleFunc("GET "+prefix+"/me", h.getMe)
+	mux.HandleFunc("GET "+prefix+"/audit", h.getAudit)
 	mux.HandleFunc("GET "+prefix+"/datasources", h.listDataSources)
 	mux.HandleFunc("GET "+prefix+"/signals", h.listSignals)
 	mux.HandleFunc("GET "+prefix+"/signals/search", h.searchSignals)
@@ -118,15 +128,93 @@ func (h *Handler) getMe(w http.ResponseWriter, r *http.Request) {
 		"level":        h.policy.Level(user).String(),
 		"groups":       groups,
 		"canEditLogic": h.policy.CanEditLogic(user),
+		"canViewAudit": h.policy.CanViewAudit(user),
 	})
 }
 
+// ── /audit ────────────────────────────────────────────────────────────────────
+
+// getAudit returns audit-log entries matching the query filters. Access is
+// restricted to users permitted by CanViewAudit (the audit-readers allowlist).
+// Filters: start, end (RFC3339), user, action, ds, signal, limit.
+func (h *Handler) getAudit(w http.ResponseWriter, r *http.Request) {
+	if !h.policy.CanViewAudit(caller(r)) {
+		jsonError(w, http.StatusForbidden, "you are not permitted to view the audit log")
+		return
+	}
+	q := r.URL.Query()
+	f := audit.Filter{
+		Actor:  q.Get("user"),
+		Action: q.Get("action"),
+		DS:     q.Get("ds"),
+		Signal: q.Get("signal"),
+	}
+	if v := q.Get("start"); v != "" {
+		t, err := time.Parse(time.RFC3339, v)
+		if err != nil {
+			jsonError(w, http.StatusBadRequest, "invalid start time (want RFC3339): "+v)
+			return
+		}
+		f.Start = t
+	}
+	if v := q.Get("end"); v != "" {
+		t, err := time.Parse(time.RFC3339, v)
+		if err != nil {
+			jsonError(w, http.StatusBadRequest, "invalid end time (want RFC3339): "+v)
+			return
+		}
+		f.End = t
+	}
+	if v := q.Get("limit"); v != "" {
+		if n, err := strconv.Atoi(v); err == nil {
+			f.Limit = n
+		}
+	}
+	events, err := h.audit.Query(f)
+	if err != nil {
+		h.log.Error("audit query", "err", err)
+		jsonError(w, http.StatusInternalServerError, err.Error())
+		return
+	}
+	jsonOK(w, events)
+}
+
 // ── access helpers ────────────────────────────────────────────────────────────
 
 // caller returns the resolved end-user identity for the request (set by the
 // access middleware).
 func caller(r *http.Request) string { return access.UserFrom(r.Context()) }
 
+// clientIP returns the best-effort client address for audit attribution,
+// preferring the proxy-set X-Forwarded-For / X-Real-IP headers.
+func clientIP(r *http.Request) string {
+	if xff := r.Header.Get("X-Forwarded-For"); xff != "" {
+		if i := strings.IndexByte(xff, ','); i >= 0 {
+			return strings.TrimSpace(xff[:i])
+		}
+		return strings.TrimSpace(xff)
+	}
+	if xr := r.Header.Get("X-Real-IP"); xr != "" {
+		return strings.TrimSpace(xr)
+	}
+	if host, _, err := net.SplitHostPort(r.RemoteAddr); err == nil {
+		return host
+	}
+	return r.RemoteAddr
+}
+
+// recordMutation appends a successful configuration change to the audit log.
+func (h *Handler) recordMutation(r *http.Request, action, detail string) {
+	h.audit.Record(audit.Event{
+		Actor:     caller(r),
+		ActorType: audit.ActorUser,
+		Action:    action,
+		Detail:    detail,
+		IP:        clientIP(r),
+		Outcome:   audit.OutcomeOK,
+	})
+}
+
 // capByGlobal lowers a per-panel/folder permission to what the user's global
 // access level allows: read-only users can never exceed read, no-access users
 // get nothing.
@@ -490,6 +578,7 @@ func (h *Handler) createInterface(w http.ResponseWriter, r *http.Request) {
 			h.log.Error("record panel ownership", "id", id, "err", err)
 		}
 	}
+	h.recordMutation(r, "interface.create", id)
 	w.Header().Set("Content-Type", "application/json")
 	w.WriteHeader(http.StatusCreated)
 	_ = json.NewEncoder(w).Encode(map[string]string{"id": id})
@@ -580,6 +669,7 @@ func (h *Handler) updateInterface(w http.ResponseWriter, r *http.Request) {
 		}
 		return
 	}
+	h.recordMutation(r, "interface.update", id)
 	w.WriteHeader(http.StatusNoContent)
 }
 
@@ -721,6 +811,7 @@ func (h *Handler) deleteInterface(w http.ResponseWriter, r *http.Request) {
 	if err := h.acl.DeletePanel(id); err != nil {
 		h.log.Error("delete panel ACL", "id", id, "err", err)
 	}
+	h.recordMutation(r, "interface.delete", id)
 	w.WriteHeader(http.StatusNoContent)
 }
 
@@ -1123,6 +1214,7 @@ func (h *Handler) createControlLogic(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 	h.ctrlEngine.Reload()
+	h.recordMutation(r, "controllogic.create", g.ID+" "+g.Name)
 	w.WriteHeader(http.StatusCreated)
 	jsonOK(w, g)
 }
@@ -1152,6 +1244,7 @@ func (h *Handler) updateControlLogic(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 	h.ctrlEngine.Reload()
+	h.recordMutation(r, "controllogic.update", g.ID+" "+g.Name)
 	jsonOK(w, g)
 }
 
@@ -1164,11 +1257,13 @@ func (h *Handler) deleteControlLogic(w http.ResponseWriter, r *http.Request) {
 		jsonError(w, http.StatusForbidden, "you are not permitted to edit logic")
 		return
 	}
-	if err := h.ctrlLogic.Delete(r.PathValue("id")); err != nil {
+	id := r.PathValue("id")
-		jsonError(w, http.StatusNotFound, "control logic graph not found: "+r.PathValue("id"))
+	if err := h.ctrlLogic.Delete(id); err != nil {
+		jsonError(w, http.StatusNotFound, "control logic graph not found: "+id)
 		return
 	}
 	h.ctrlEngine.Reload()
+	h.recordMutation(r, "controllogic.delete", id)
 	w.WriteHeader(http.StatusNoContent)
 }
 

internal/api/api_test.go

@@ -14,6 +14,7 @@ import (
 
 	"github.com/uopi/uopi/internal/access"
 	"github.com/uopi/uopi/internal/api"
+	"github.com/uopi/uopi/internal/audit"
 	"github.com/uopi/uopi/internal/broker"
 	"github.com/uopi/uopi/internal/controllogic"
 	"github.com/uopi/uopi/internal/datasource/stub"
@@ -50,10 +51,10 @@ func setup(t *testing.T) (*httptest.Server, func()) {
 	if err != nil {
 		t.Fatal("controllogic.NewStore:", err)
 	}
-	clEngine := controllogic.NewEngine(ctx, brk, clStore, log)
+	clEngine := controllogic.NewEngine(ctx, brk, clStore, audit.Nop(), log)
 
 	mux := http.NewServeMux()
-	api.New(brk, nil, store, access.New("", nil, nil, nil), acl, clStore, clEngine, "", "", log).Register(mux, "/api/v1")
+	api.New(brk, nil, store, access.New("", nil, nil, nil, nil), acl, clStore, clEngine, audit.Nop(), "", "", log).Register(mux, "/api/v1")
 
 	srv := httptest.NewServer(mux)
 	return srv, func() {
@@ -214,7 +215,9 @@ func TestSearchSignals(t *testing.T) {
 	resp := get(t, srv, "/api/v1/signals/search?q=sine")
 	assertStatus(t, resp, http.StatusOK)
 
-	var signals []struct{ Name string `json:"name"` }
+	var signals []struct {
+		Name string `json:"name"`
+	}
 	readJSON(t, resp, &signals)
 
 	for _, s := range signals {
@@ -259,7 +262,9 @@ func TestInterfaceCRUD(t *testing.T) {
 	// Create
 	resp = postRaw(t, srv, "/api/v1/interfaces", "application/xml", []byte(sampleXML))
 	assertStatus(t, resp, http.StatusCreated)
-	var created struct{ ID string `json:"id"` }
+	var created struct {
+		ID string `json:"id"`
+	}
 	readJSON(t, resp, &created)
 	if created.ID == "" {
 		t.Fatal("expected non-empty ID from create")
@@ -303,7 +308,9 @@ func TestInterfaceCRUD(t *testing.T) {
 		t.Fatal("clone:", err)
 	}
 	assertStatus(t, resp, http.StatusCreated)
-	var cloned struct{ ID string `json:"id"` }
+	var cloned struct {
+		ID string `json:"id"`
+	}
 	readJSON(t, resp, &cloned)
 	if cloned.ID == created.ID {
 		t.Error("clone produced same ID as original")

internal/audit/audit.go

@@ -0,0 +1,65 @@
+// Package audit records system-affecting actions (signal writes by users or the
+// control-logic engine, interface and control-logic mutations) to an append-only
+// SQLite log that audit staff can query later. It is enabled via [audit] in the
+// config; when disabled a no-op Recorder is used so call sites need no guards.
+package audit
+
+import "time"
+
+// Actor types distinguish human-initiated actions from automated ones.
+const (
+	ActorUser   = "user"   // action attributed to an authenticated end-user
+	ActorSystem = "system" // action performed by the control-logic engine
+)
+
+// Outcomes record whether the action succeeded.
+const (
+	OutcomeOK    = "ok"
+	OutcomeError = "error"
+)
+
+// Event is a single audit record. Optional fields are omitted from the database
+// when empty. Time defaults to the current time when zero.
+type Event struct {
+	Time      time.Time `json:"time"`
+	Actor     string    `json:"actor"`            // username, or graph name for system actions
+	ActorType string    `json:"actorType"`        // ActorUser | ActorSystem
+	Action    string    `json:"action"`           // e.g. "signal.write", "interface.update"
+	DS        string    `json:"ds,omitempty"`     // data source (signal writes)
+	Signal    string    `json:"signal,omitempty"` // signal / target name
+	Value     string    `json:"value,omitempty"`  // serialised written value
+	Detail    string    `json:"detail,omitempty"` // free-form context (id, graph, trigger)
+	IP        string    `json:"ip,omitempty"`     // client address (user actions)
+	Outcome   string    `json:"outcome"`          // OutcomeOK | OutcomeError
+	Error     string    `json:"error,omitempty"`  // message when Outcome==OutcomeError
+}
+
+// Filter selects a subset of events for Query. Zero-valued fields are ignored.
+type Filter struct {
+	Start  time.Time
+	End    time.Time
+	Actor  string
+	Action string
+	DS     string
+	Signal string
+	Limit  int // <=0 means a default cap is applied
+}
+
+// Recorder appends events and answers queries. Implementations must be safe for
+// concurrent use and Record must never block the caller for long.
+type Recorder interface {
+	Record(Event)
+	Query(Filter) ([]Event, error)
+	Close() error
+}
+
+// nopRecorder is used when auditing is disabled. It discards every event.
+type nopRecorder struct{}
+
+func (nopRecorder) Record(Event)                  {}
+func (nopRecorder) Query(Filter) ([]Event, error) { return []Event{}, nil }
+func (nopRecorder) Close() error                  { return nil }
+
+// Nop returns a Recorder that discards everything. Call sites can hold a Recorder
+// unconditionally and call Record without checking whether auditing is enabled.
+func Nop() Recorder { return nopRecorder{} }

internal/audit/sqlite.go

@@ -0,0 +1,183 @@
+package audit
+
+import (
+	"database/sql"
+	"fmt"
+	"log/slog"
+	"strings"
+	"sync"
+	"time"
+
+	_ "modernc.org/sqlite" // pure-Go SQLite driver (no CGo, keeps the single static binary)
+)
+
+// defaultQueryLimit caps how many rows Query returns when the filter does not
+// specify a smaller limit, protecting the API and UI from unbounded result sets.
+const defaultQueryLimit = 1000
+
+// writeBuffer is the depth of the async insert queue. When full, Record falls
+// back to a synchronous insert so events are never silently dropped.
+const writeBuffer = 4096
+
+// sqliteRecorder appends events to a SQLite database. Inserts are normally
+// handled by a background goroutine so Record does not block the calling write
+// path; the queue has a synchronous fallback to guarantee durability under load.
+type sqliteRecorder struct {
+	db  *sql.DB
+	log *slog.Logger
+
+	ch     chan Event
+	wg     sync.WaitGroup
+	closed chan struct{}
+	once   sync.Once
+}
+
+// NewSQLite opens (creating if needed) the audit database at path and starts the
+// background writer. The returned Recorder must be Closed on shutdown.
+func NewSQLite(path string, log *slog.Logger) (Recorder, error) {
+	// WAL + a busy timeout let the async writer and synchronous query/fallback
+	// paths share the file without "database is locked" errors.
+	dsn := fmt.Sprintf("file:%s?_pragma=busy_timeout(5000)&_pragma=journal_mode(WAL)&_pragma=synchronous(NORMAL)", path)
+	db, err := sql.Open("sqlite", dsn)
+	if err != nil {
+		return nil, fmt.Errorf("open audit db: %w", err)
+	}
+	if _, err := db.Exec(schema); err != nil {
+		_ = db.Close()
+		return nil, fmt.Errorf("init audit schema: %w", err)
+	}
+	r := &sqliteRecorder{
+		db:     db,
+		log:    log,
+		ch:     make(chan Event, writeBuffer),
+		closed: make(chan struct{}),
+	}
+	r.wg.Add(1)
+	go r.writeLoop()
+	return r, nil
+}
+
+const schema = `
+CREATE TABLE IF NOT EXISTS audit_log (
+	id         INTEGER PRIMARY KEY AUTOINCREMENT,
+	ts_ns      INTEGER NOT NULL,
+	actor      TEXT NOT NULL,
+	actor_type TEXT NOT NULL,
+	action     TEXT NOT NULL,
+	ds         TEXT NOT NULL DEFAULT '',
+	signal     TEXT NOT NULL DEFAULT '',
+	value      TEXT NOT NULL DEFAULT '',
+	detail     TEXT NOT NULL DEFAULT '',
+	ip         TEXT NOT NULL DEFAULT '',
+	outcome    TEXT NOT NULL DEFAULT 'ok',
+	error      TEXT NOT NULL DEFAULT ''
+);
+CREATE INDEX IF NOT EXISTS idx_audit_ts ON audit_log(ts_ns);
+CREATE INDEX IF NOT EXISTS idx_audit_actor ON audit_log(actor);
+CREATE INDEX IF NOT EXISTS idx_audit_action ON audit_log(action);
+`
+
+func (r *sqliteRecorder) Record(e Event) {
+	if e.Time.IsZero() {
+		e.Time = time.Now()
+	}
+	if e.Outcome == "" {
+		e.Outcome = OutcomeOK
+	}
+	select {
+	case <-r.closed:
+		// Recorder is shutting down; best-effort synchronous insert.
+		r.insert(e)
+	case r.ch <- e:
+	default:
+		// Queue full: write synchronously rather than drop an audit record.
+		r.insert(e)
+	}
+}
+
+func (r *sqliteRecorder) writeLoop() {
+	defer r.wg.Done()
+	for e := range r.ch {
+		r.insert(e)
+	}
+}
+
+func (r *sqliteRecorder) insert(e Event) {
+	_, err := r.db.Exec(
+		`INSERT INTO audit_log (ts_ns, actor, actor_type, action, ds, signal, value, detail, ip, outcome, error)
+		 VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)`,
+		e.Time.UnixNano(), e.Actor, e.ActorType, e.Action,
+		e.DS, e.Signal, e.Value, e.Detail, e.IP, e.Outcome, e.Error,
+	)
+	if err != nil {
+		r.log.Error("audit: insert failed", "action", e.Action, "err", err)
+	}
+}
+
+func (r *sqliteRecorder) Query(f Filter) ([]Event, error) {
+	var where []string
+	var args []any
+	if !f.Start.IsZero() {
+		where = append(where, "ts_ns >= ?")
+		args = append(args, f.Start.UnixNano())
+	}
+	if !f.End.IsZero() {
+		where = append(where, "ts_ns <= ?")
+		args = append(args, f.End.UnixNano())
+	}
+	if f.Actor != "" {
+		where = append(where, "actor = ?")
+		args = append(args, f.Actor)
+	}
+	if f.Action != "" {
+		where = append(where, "action = ?")
+		args = append(args, f.Action)
+	}
+	if f.DS != "" {
+		where = append(where, "ds = ?")
+		args = append(args, f.DS)
+	}
+	if f.Signal != "" {
+		where = append(where, "signal LIKE ?")
+		args = append(args, "%"+f.Signal+"%")
+	}
+	limit := f.Limit
+	if limit <= 0 || limit > defaultQueryLimit {
+		limit = defaultQueryLimit
+	}
+
+	q := "SELECT ts_ns, actor, actor_type, action, ds, signal, value, detail, ip, outcome, error FROM audit_log"
+	if len(where) > 0 {
+		q += " WHERE " + strings.Join(where, " AND ")
+	}
+	q += " ORDER BY ts_ns DESC LIMIT ?"
+	args = append(args, limit)
+
+	rows, err := r.db.Query(q, args...)
+	if err != nil {
+		return nil, fmt.Errorf("query audit log: %w", err)
+	}
+	defer rows.Close()
+
+	out := []Event{}
+	for rows.Next() {
+		var e Event
+		var tsNs int64
+		if err := rows.Scan(&tsNs, &e.Actor, &e.ActorType, &e.Action,
+			&e.DS, &e.Signal, &e.Value, &e.Detail, &e.IP, &e.Outcome, &e.Error); err != nil {
+			return nil, fmt.Errorf("scan audit row: %w", err)
+		}
+		e.Time = time.Unix(0, tsNs)
+		out = append(out, e)
+	}
+	return out, rows.Err()
+}
+
+func (r *sqliteRecorder) Close() error {
+	r.once.Do(func() {
+		close(r.closed)
+		close(r.ch)
+	})
+	r.wg.Wait()
+	return r.db.Close()
+}

internal/audit/sqlite_test.go

@@ -0,0 +1,68 @@
+package audit
+
+import (
+	"log/slog"
+	"path/filepath"
+	"testing"
+	"time"
+)
+
+func TestSQLiteRoundTrip(t *testing.T) {
+	path := filepath.Join(t.TempDir(), "audit.db")
+	rec, err := NewSQLite(path, slog.Default())
+	if err != nil {
+		t.Fatal("NewSQLite:", err)
+	}
+	defer rec.Close()
+
+	base := time.Now()
+	rec.Record(Event{Time: base, Actor: "alice", ActorType: ActorUser, Action: "signal.write", DS: "epics", Signal: "PV:A", Value: "1.5"})
+	rec.Record(Event{Time: base.Add(time.Second), Actor: "flow1", ActorType: ActorSystem, Action: "signal.write", DS: "epics", Signal: "PV:B", Value: "0"})
+	rec.Record(Event{Time: base.Add(2 * time.Second), Actor: "bob", ActorType: ActorUser, Action: "interface.update", Detail: "panel-1", Outcome: OutcomeError, Error: "denied"})
+
+	// Flush the async writer.
+	if err := rec.Close(); err != nil {
+		t.Fatal("Close:", err)
+	}
+	rec, err = NewSQLite(path, slog.Default())
+	if err != nil {
+		t.Fatal("reopen:", err)
+	}
+	defer rec.Close()
+
+	all, err := rec.Query(Filter{})
+	if err != nil {
+		t.Fatal("Query:", err)
+	}
+	if len(all) != 3 {
+		t.Fatalf("got %d events, want 3", len(all))
+	}
+	// Newest first.
+	if all[0].Actor != "bob" {
+		t.Errorf("first actor = %q, want bob", all[0].Actor)
+	}
+
+	byActor, err := rec.Query(Filter{Actor: "alice"})
+	if err != nil {
+		t.Fatal("Query actor:", err)
+	}
+	if len(byActor) != 1 || byActor[0].Signal != "PV:A" {
+		t.Errorf("actor filter = %+v, want one PV:A event", byActor)
+	}
+
+	byAction, err := rec.Query(Filter{Action: "signal.write"})
+	if err != nil {
+		t.Fatal("Query action:", err)
+	}
+	if len(byAction) != 2 {
+		t.Errorf("action filter returned %d, want 2", len(byAction))
+	}
+
+	since, err := rec.Query(Filter{Start: base.Add(1500 * time.Millisecond)})
+	if err != nil {
+		t.Fatal("Query start:", err)
+	}
+	if len(since) != 1 || since[0].Actor != "bob" {
+		t.Errorf("time filter = %+v, want one bob event", since)
+	}
+}

internal/config/config.go

@@ -12,10 +12,23 @@ import (
 type Config struct {
 	Server     ServerConfig     `toml:"server"`
 	Datasource DatasourceConfig `toml:"datasource"`
+	Audit      AuditConfig      `toml:"audit"`
 	// Groups are named sets of users, referenced by panel sharing rules.
 	Groups []GroupDef `toml:"groups"`
 }
 
+// AuditConfig controls the audit trail. When enabled, every user and automated
+// action that could affect the controlled system (signal writes, control-logic
+// changes) is recorded to a SQLite database for later review by audit staff.
+type AuditConfig struct {
+	Enabled bool   `toml:"enabled"`
+	DBPath  string `toml:"db_path"` // SQLite file; default {storage_dir}/audit.db
+	// Readers lists users or group names allowed to view the audit log. Empty
+	// leaves viewing unrestricted (any caller with read access). Anonymous /
+	// trusted-LAN callers are always permitted.
+	Readers []string `toml:"readers"`
+}
+
 // GroupDef is a named set of users defined as [[groups]] in the config file.
 type GroupDef struct {
 	Name    string   `toml:"name"`
@@ -71,10 +84,10 @@ type StubConfig struct {
 }
 
 type EPICSConfig struct {
-	Enabled          bool     `toml:"enabled"`
+	Enabled              bool     `toml:"enabled"`
-	CAAddrList       string   `toml:"ca_addr_list"`
+	CAAddrList           string   `toml:"ca_addr_list"`
-	ArchiveURL       string   `toml:"archive_url"`
+	ArchiveURL           string   `toml:"archive_url"`
-	ChannelFinderURL string   `toml:"channel_finder_url"`
+	ChannelFinderURL     string   `toml:"channel_finder_url"`
 	AutoSyncFilter       string   `toml:"auto_sync_filter"`
 	AutoSyncFromArchiver bool     `toml:"auto_sync_from_archiver"`
 	PVNames              []string `toml:"pv_names"`
@@ -141,6 +154,15 @@ func applyEnv(cfg *Config) {
 	if v := env("UOPI_SERVER_LOGIC_EDITORS"); v != "" {
 		cfg.Server.LogicEditors = strings.Fields(v)
 	}
+	if v := env("UOPI_AUDIT_ENABLED"); v != "" {
+		cfg.Audit.Enabled = (v == "true" || v == "YES")
+	}
+	if v := env("UOPI_AUDIT_DB_PATH"); v != "" {
+		cfg.Audit.DBPath = v
+	}
+	if v := env("UOPI_AUDIT_READERS"); v != "" {
+		cfg.Audit.Readers = strings.Fields(v)
+	}
 	if v := env("UOPI_EPICS_CA_ADDR_LIST"); v != "" {
 		cfg.Datasource.EPICS.CAAddrList = v
 	}

internal/controllogic/engine.go

@@ -8,8 +8,10 @@ import (
 	"strconv"
 	"strings"
 	"sync"
+	"sync/atomic"
 	"time"
 
+	"github.com/uopi/uopi/internal/audit"
 	"github.com/uopi/uopi/internal/broker"
 )
 
@@ -25,23 +27,46 @@ const (
 type Engine struct {
 	broker *broker.Broker
 	store  *Store
+	audit  audit.Recorder
 	log    *slog.Logger
 	root   context.Context
 
-	mu       sync.Mutex
+	mu     sync.Mutex
-	cancel   context.CancelFunc // cancels the current generation
+	cancel context.CancelFunc // cancels the current generation
-	wg       *sync.WaitGroup    // tracks the current generation's goroutines
+	wg     *sync.WaitGroup    // tracks the current generation's goroutines
+
+	// notifier delivers action.dialog requests to connected clients. Stored in
+	// an atomic so flow goroutines can read it without taking e.mu (which Reload
+	// holds while it waits for those same goroutines to drain).
+	notifier atomic.Value // notifierBox
 
 	// Shared live signal cache for the current generation (key "ds\0name").
 	liveMu sync.RWMutex
 	live   map[string]float64
 }
 
-// NewEngine creates an engine bound to root. Call Reload to start it.
+// notifierBox wraps a Notifier so atomic.Value always sees one concrete type.
-func NewEngine(root context.Context, brk *broker.Broker, store *Store, log *slog.Logger) *Engine {
+type notifierBox struct{ n Notifier }
+
+// dialogSeq generates unique action.dialog ids across all graphs.
+var dialogSeq uint64
+
+// SetNotifier installs the sink for action.dialog requests. Safe to call once
+// at startup before or after Reload; it is read lock-free by running flows.
+func (e *Engine) SetNotifier(n Notifier) {
+	e.notifier.Store(notifierBox{n: n})
+}
+
+// NewEngine creates an engine bound to root. Call Reload to start it. rec records
+// the writes performed by flows; pass audit.Nop() to disable auditing.
+func NewEngine(root context.Context, brk *broker.Broker, store *Store, rec audit.Recorder, log *slog.Logger) *Engine {
+	if rec == nil {
+		rec = audit.Nop()
+	}
 	return &Engine{
 		broker: brk,
 		store:  store,
+		audit:  rec,
 		log:    log,
 		root:   root,
 		live:   map[string]float64{},
@@ -227,9 +252,45 @@ func (e *Engine) write(cg *compiledGraph, target string, val float64) {
 		e.log.Warn("control logic: write to unknown data source", "ds", ds, "signal", name)
 		return
 	}
+	ev := audit.Event{
+		Actor:     cg.name,
+		ActorType: audit.ActorSystem,
+		Action:    "signal.write",
+		DS:        ds,
+		Signal:    name,
+		Value:     strconv.FormatFloat(val, 'g', -1, 64),
+		Detail:    "control logic: " + cg.name,
+		Outcome:   audit.OutcomeOK,
+	}
 	if err := src.Write(e.root, name, val); err != nil {
 		e.log.Warn("control logic: write failed", "ds", ds, "signal", name, "err", err)
+		ev.Outcome = audit.OutcomeError
+		ev.Error = err.Error()
 	}
+	e.audit.Record(ev)
+}
+
+// emitDialog delivers an action.dialog node's request to the installed Notifier
+// (the WebSocket dialog hub). It is lock-free so it never deadlocks against a
+// concurrent Reload that is waiting for this flow goroutine to finish.
+func (e *Engine) emitDialog(n Node) {
+	box, _ := e.notifier.Load().(notifierBox)
+	if box.n == nil {
+		return
+	}
+	kind := strings.TrimSpace(n.param("kind"))
+	if kind != "error" && kind != "input" {
+		kind = "info"
+	}
+	box.n.Notify(Dialog{
+		ID:      strconv.FormatUint(atomic.AddUint64(&dialogSeq, 1), 10),
+		Kind:    kind,
+		Title:   n.param("title"),
+		Message: n.param("message"),
+		Target:  strings.TrimSpace(n.param("target")),
+		Users:   splitCSV(n.param("users")),
+		Groups:  splitCSV(n.param("groups")),
+	})
 }
 
 // ── compiled graph ─────────────────────────────────────────────────────────────
@@ -245,11 +306,11 @@ type compiledGraph struct {
 	genCtx context.Context
 	wg     *sync.WaitGroup
 
-	name  string
+	name string
-	byId  map[string]Node
+	byId map[string]Node
-	out   map[string][]wireOut
+	out  map[string][]wireOut
-	inc   map[string][]string // incoming source ids per node (for gates)
+	inc  map[string][]string // incoming source ids per node (for gates)
-	refs  map[string]RefLite  // unique signals to subscribe (excl. sys/local)
+	refs map[string]RefLite  // unique signals to subscribe (excl. sys/local)
 
 	watchers map[string][]string // signal key → trigger node ids
 	luaNodes map[string]*luaRuntime
@@ -638,6 +699,10 @@ func (cg *compiledGraph) run(nodeID string, ctx *runCtx) {
 		cg.runLua(node.ID, ctx)
 		cg.follow(node.ID, "out", ctx)
 
+	case "action.dialog":
+		cg.engine.emitDialog(node)
+		cg.follow(node.ID, "out", ctx)
+
 	default:
 		cg.follow(node.ID, "out", ctx)
 	}

internal/controllogic/model.go

@@ -29,6 +29,8 @@ package controllogic
 //	action.delay      — waits `ms` before continuing.
 //	action.log        — logs an expression value to the server log.
 //	action.lua        — runs a sandboxed Lua script with get/set/log host funcs.
+//	action.dialog     — pushes an info/error/input dialog to connected clients
+//	                    filtered by user/group; input responses write `target`.
 
 // Node is a single node in a control-logic graph. Params are stored as strings
 // (matching the panel logic model) and parsed per-kind by the engine.

internal/controllogic/notify.go

@@ -0,0 +1,37 @@
+package controllogic
+
+import "strings"
+
+// Dialog is a user-facing notification or input request emitted by an
+// action.dialog node. It is delivered to connected clients whose identity
+// matches Users/Groups (both empty = everyone). For an "input" dialog the
+// client's response is written back to Target (a "ds:name" reference, e.g.
+// "srv:approved") so control logic can read it on a later activation.
+type Dialog struct {
+	ID      string   `json:"id"`
+	Kind    string   `json:"kind"` // "info" | "error" | "input"
+	Title   string   `json:"title"`
+	Message string   `json:"message"`
+	Target  string   `json:"target,omitempty"`
+	Users   []string `json:"users,omitempty"`
+	Groups  []string `json:"groups,omitempty"`
+}
+
+// Notifier delivers control-logic dialogs to connected clients. The server
+// implements it; the engine calls Notify when an action.dialog node runs.
+// Notify must not block (the hub fans out without waiting on slow clients).
+type Notifier interface {
+	Notify(Dialog)
+}
+
+// splitCSV parses a comma-separated user/group filter into trimmed,
+// non-empty tokens. An empty string yields a nil slice (no filter).
+func splitCSV(s string) []string {
+	var out []string
+	for _, p := range strings.Split(s, ",") {
+		if t := strings.TrimSpace(p); t != "" {
+			out = append(out, t)
+		}
+	}
+	return out
+}

internal/controllogic/store.go

@@ -7,6 +7,7 @@ import (
 	"os"
 	"path/filepath"
 	"sync"
+	"time"
 )
 
 const definitionsFile = "controllogic.json"
@@ -17,16 +18,18 @@ var ErrNotFound = errors.New("control logic graph not found")
 // Store persists control-logic graphs as a single JSON file in the storage dir.
 // Writes are atomic (tmp file + rename); all access is mutex-guarded.
 type Store struct {
-	mu    sync.RWMutex
+	mu       sync.RWMutex
-	path  string
+	path     string
-	items map[string]Graph
+	trashDir string
+	items    map[string]Graph
 }
 
 // NewStore opens (or initialises) the control-logic store under storageDir.
 func NewStore(storageDir string) (*Store, error) {
 	s := &Store{
-		path:  filepath.Join(storageDir, definitionsFile),
+		path:     filepath.Join(storageDir, definitionsFile),
-		items: map[string]Graph{},
+		trashDir: filepath.Join(storageDir, "trash", "controllogic"),
+		items:    map[string]Graph{},
 	}
 	if err := s.load(); err != nil {
 		return nil, err
@@ -99,13 +102,32 @@ func (s *Store) Save(g Graph) error {
 	return s.saveLocked()
 }
 
-// Delete removes a graph by id.
+// Delete removes a graph by id, first writing a copy into the trash folder so it
+// can be recovered if needed. The trash backup is best-effort: a failure to write
+// it does not prevent the delete (but is reported).
 func (s *Store) Delete(id string) error {
 	s.mu.Lock()
 	defer s.mu.Unlock()
-	if _, ok := s.items[id]; !ok {
+	g, ok := s.items[id]
+	if !ok {
 		return ErrNotFound
 	}
+	if err := s.trash(g); err != nil {
+		return fmt.Errorf("move control logic to trash: %w", err)
+	}
 	delete(s.items, id)
 	return s.saveLocked()
 }
+
+// trash writes a single graph as a timestamped JSON file under the trash folder.
+func (s *Store) trash(g Graph) error {
+	if err := os.MkdirAll(s.trashDir, 0o755); err != nil {
+		return err
+	}
+	data, err := json.MarshalIndent(g, "", "  ")
+	if err != nil {
+		return err
+	}
+	dst := filepath.Join(s.trashDir, fmt.Sprintf("%s.%d.json", g.ID, time.Now().UnixMilli()))
+	return os.WriteFile(dst, data, 0o644)
+}

internal/datasource/epics/archive.go

@@ -112,6 +112,8 @@ func fetchArchiveHistory(ctx context.Context, archiveURL, signal string, start,
 			Timestamp: ts,
 			Data:      data,
 			Quality:   q,
+			Severity:  p.Severity,
+			Status:    p.Status,
 		})
 	}
 

internal/datasource/epics/ca_callback.go

@@ -22,7 +22,7 @@ import (
 //
 //export goCAMonitorCallback
 func goCAMonitorCallback(handle C.uintptr_t, dbrType C.int, count C.long,
-	dbr unsafe.Pointer, severity C.int, epicsTimeSecs C.double) {
+	dbr unsafe.Pointer, severity C.int, status C.int, epicsTimeSecs C.double) {
 
 	h := uintptr(handle)
 
@@ -79,7 +79,13 @@ func goCAMonitorCallback(handle C.uintptr_t, dbrType C.int, count C.long,
 		data = float64(0)
 	}
 
-	v := datasource.Value{Timestamp: ts, Data: data, Quality: q}
+	v := datasource.Value{
+		Timestamp: ts,
+		Data:      data,
+		Quality:   q,
+		Severity:  int(severity),
+		Status:    int(status),
+	}
 
 	// Look up the subscription channel under the global handle table lock and
 	// perform a non-blocking send so we never stall the CA callback thread.
@@ -129,6 +135,7 @@ func goCAConnectionCallback(handle C.uintptr_t, connected C.int) {
 				Timestamp: time.Now(),
 				Data:      float64(0),
 				Quality:   datasource.QualityBad,
+				Severity:  3, // INVALID
 			}
 			select {
 			case ch <- v:

internal/datasource/epics/ca_wrapper.h

@@ -13,7 +13,7 @@
  * goCAConnectionCallback is called when a channel connects or disconnects.
  */
 extern void goCAMonitorCallback(uintptr_t handle, int dbrType, long count,
-                                void *dbr, int severity,
+                                void *dbr, int severity, int status,
                                 double epicsTimeSecs);
 extern void goCAConnectionCallback(uintptr_t handle, int connected);
 
@@ -30,9 +30,10 @@ static void caMonitorCallbackShim(struct event_handler_args args) {
 
     double timeSecs = 0.0;
     int    severity = 0;
+    int    status   = 0;
 
     /*
-     * Determine the timestamp and alarm severity from the DBR type.
+     * Determine the timestamp and alarm severity/status from the DBR type.
      * We request DBR_TIME_* types so the timestamp is embedded in the value
      * buffer right after the alarm fields (struct dbr_time_double et al.).
      */
@@ -41,36 +42,42 @@ static void caMonitorCallbackShim(struct event_handler_args args) {
         const struct dbr_time_double *p = (const struct dbr_time_double *)args.dbr;
         timeSecs = (double)p->stamp.secPastEpoch + (double)p->stamp.nsec / 1e9;
         severity = (int)p->severity;
+        status   = (int)p->status;
         break;
     }
     case DBR_TIME_FLOAT: {
         const struct dbr_time_float *p = (const struct dbr_time_float *)args.dbr;
         timeSecs = (double)p->stamp.secPastEpoch + (double)p->stamp.nsec / 1e9;
         severity = (int)p->severity;
+        status   = (int)p->status;
         break;
     }
     case DBR_TIME_LONG: {
         const struct dbr_time_long *p = (const struct dbr_time_long *)args.dbr;
         timeSecs = (double)p->stamp.secPastEpoch + (double)p->stamp.nsec / 1e9;
         severity = (int)p->severity;
+        status   = (int)p->status;
         break;
     }
     case DBR_TIME_SHORT: {
         const struct dbr_time_short *p = (const struct dbr_time_short *)args.dbr;
         timeSecs = (double)p->stamp.secPastEpoch + (double)p->stamp.nsec / 1e9;
         severity = (int)p->severity;
+        status   = (int)p->status;
         break;
     }
     case DBR_TIME_STRING: {
         const struct dbr_time_string *p = (const struct dbr_time_string *)args.dbr;
         timeSecs = (double)p->stamp.secPastEpoch + (double)p->stamp.nsec / 1e9;
         severity = (int)p->severity;
+        status   = (int)p->status;
         break;
     }
     case DBR_TIME_ENUM: {
         const struct dbr_time_enum *p = (const struct dbr_time_enum *)args.dbr;
         timeSecs = (double)p->stamp.secPastEpoch + (double)p->stamp.nsec / 1e9;
         severity = (int)p->severity;
+        status   = (int)p->status;
         break;
     }
     default:
@@ -78,7 +85,7 @@ static void caMonitorCallbackShim(struct event_handler_args args) {
     }
 
     goCAMonitorCallback((uintptr_t)args.usr, (int)args.type, (long)args.count,
-                        (void *)args.dbr, severity, timeSecs);
+                        (void *)args.dbr, severity, status, timeSecs);
 }
 
 /*

internal/datasource/epics/noop.go

@@ -275,6 +275,8 @@ func (e *EPICS) timeValueToDS(signal string, tv proto.TimeValue) datasource.Valu
 		Timestamp: tv.Timestamp,
 		Data:      data,
 		Quality:   quality,
+		Severity:  int(tv.Severity),
+		Status:    int(tv.Status),
 	}
 }
 

internal/datasource/iface.go

@@ -45,6 +45,8 @@ type Value struct {
 	Timestamp  time.Time
 	Data       any // float64 | []float64 | string | int64 | bool
 	Quality    Quality
+	Severity   int  // raw EPICS alarm severity (0=NO_ALARM,1=MINOR,2=MAJOR,3=INVALID); 0 for sources without alarm info
+	Status     int  // raw EPICS alarm status (.STAT); 0 for sources without alarm info
 	MetaUpdate bool // if true, metadata was refreshed — dispatcher should re-send meta
 }
 

internal/datasource/pva/pva.go

@@ -180,6 +180,7 @@ func structToValue(sv pvdata.StructValue) datasource.Value {
 	val := fieldByName(sv, "value")
 	ts := extractTimestamp(sv)
 	quality := extractQuality(sv)
+	severity, status := extractSeverityStatus(sv)
 
 	var data any
 	if val != nil {
@@ -190,6 +191,8 @@ func structToValue(sv pvdata.StructValue) datasource.Value {
 		Timestamp: ts,
 		Data:      data,
 		Quality:   quality,
+		Severity:  severity,
+		Status:    status,
 	}
 }
 
@@ -329,6 +332,26 @@ func extractQuality(sv pvdata.StructValue) datasource.Quality {
 	}
 }
 
+// extractSeverityStatus pulls the raw EPICS alarm severity and status from the
+// NTScalar "alarm" struct. Returns (0, 0) when no alarm struct is present.
+func extractSeverityStatus(sv pvdata.StructValue) (severity, status int) {
+	alarm := structByName(sv, "alarm")
+	if alarm == nil {
+		return 0, 0
+	}
+	if v := fieldByName(*alarm, "severity"); v != nil {
+		if s, ok := v.(int32); ok {
+			severity = int(s)
+		}
+	}
+	if v := fieldByName(*alarm, "status"); v != nil {
+		if s, ok := v.(int32); ok {
+			status = int(s)
+		}
+	}
+	return severity, status
+}
+
 func toFloat64(v any) (float64, bool) {
 	switch x := v.(type) {
 	case float64:

internal/datasource/servervar/servervar.go

@@ -0,0 +1,212 @@
+// Package servervar provides a small persistent key/value data source for
+// "server variables": named scalar values that the server-side control-logic
+// engine writes (e.g. the state of a sequence) and that interface panels can
+// read live. Panels may read any variable; writes from panels are gated to
+// control-logic editors in the WebSocket write handler.
+package servervar
+
+import (
+	"context"
+	"encoding/json"
+	"os"
+	"path/filepath"
+	"sort"
+	"sync"
+	"time"
+
+	"github.com/uopi/uopi/internal/datasource"
+)
+
+const fileName = "servervars.json"
+
+type variable struct {
+	value float64
+	ts    time.Time
+}
+
+// Source is the "srv" data source. Variables are created on first write and
+// persisted so their last value survives a restart.
+type Source struct {
+	path string
+
+	mu     sync.RWMutex
+	vars   map[string]*variable
+	subs   map[string]map[int]chan<- datasource.Value
+	nextID int
+}
+
+// New opens (or initialises) the server-variable store under storageDir.
+func New(storageDir string) (*Source, error) {
+	s := &Source{
+		path: filepath.Join(storageDir, fileName),
+		vars: map[string]*variable{},
+		subs: map[string]map[int]chan<- datasource.Value{},
+	}
+	if err := s.load(); err != nil {
+		return nil, err
+	}
+	return s, nil
+}
+
+func (s *Source) load() error {
+	data, err := os.ReadFile(s.path)
+	if os.IsNotExist(err) {
+		return nil
+	}
+	if err != nil {
+		return err
+	}
+	var raw map[string]float64
+	if err := json.Unmarshal(data, &raw); err != nil {
+		return err
+	}
+	now := time.Now()
+	for name, v := range raw {
+		s.vars[name] = &variable{value: v, ts: now}
+	}
+	return nil
+}
+
+// saveLocked persists the current values atomically. Caller holds s.mu.
+func (s *Source) saveLocked() {
+	raw := make(map[string]float64, len(s.vars))
+	for name, v := range s.vars {
+		raw[name] = v.value
+	}
+	data, err := json.MarshalIndent(raw, "", "  ")
+	if err != nil {
+		return
+	}
+	tmp := s.path + ".tmp"
+	if err := os.WriteFile(tmp, data, 0o644); err != nil {
+		return
+	}
+	_ = os.Rename(tmp, s.path)
+}
+
+func meta(name string) datasource.Metadata {
+	return datasource.Metadata{
+		Name:        name,
+		Type:        datasource.TypeFloat64,
+		Description: "Server variable",
+		Writable:    true,
+	}
+}
+
+// Name implements datasource.DataSource.
+func (s *Source) Name() string { return "srv" }
+
+// Connect is a no-op — the store is opened in New.
+func (s *Source) Connect(_ context.Context) error { return nil }
+
+// ListSignals returns metadata for every defined server variable.
+func (s *Source) ListSignals(_ context.Context) ([]datasource.Metadata, error) {
+	s.mu.RLock()
+	defer s.mu.RUnlock()
+	names := make([]string, 0, len(s.vars))
+	for name := range s.vars {
+		names = append(names, name)
+	}
+	sort.Strings(names)
+	out := make([]datasource.Metadata, 0, len(names))
+	for _, name := range names {
+		out = append(out, meta(name))
+	}
+	return out, nil
+}
+
+// GetMetadata returns metadata for a single variable. Unknown names still report
+// writable metadata so that control logic / authorised panels may create them.
+func (s *Source) GetMetadata(_ context.Context, signal string) (datasource.Metadata, error) {
+	return meta(signal), nil
+}
+
+// Subscribe registers ch for updates and immediately delivers the current value.
+func (s *Source) Subscribe(ctx context.Context, signal string, ch chan<- datasource.Value) (datasource.CancelFunc, error) {
+	s.mu.Lock()
+	if s.subs[signal] == nil {
+		s.subs[signal] = map[int]chan<- datasource.Value{}
+	}
+	id := s.nextID
+	s.nextID++
+	s.subs[signal][id] = ch
+	cur, ok := s.vars[signal]
+	var first datasource.Value
+	if ok {
+		first = datasource.Value{Timestamp: cur.ts, Data: cur.value, Quality: datasource.QualityGood}
+	}
+	s.mu.Unlock()
+
+	if ok {
+		go func() {
+			select {
+			case ch <- first:
+			case <-ctx.Done():
+			}
+		}()
+	}
+
+	return func() {
+		s.mu.Lock()
+		if m := s.subs[signal]; m != nil {
+			delete(m, id)
+			if len(m) == 0 {
+				delete(s.subs, signal)
+			}
+		}
+		s.mu.Unlock()
+	}, nil
+}
+
+func toFloat64(v any) float64 {
+	switch x := v.(type) {
+	case float64:
+		return x
+	case float32:
+		return float64(x)
+	case int:
+		return float64(x)
+	case int64:
+		return float64(x)
+	case bool:
+		if x {
+			return 1
+		}
+		return 0
+	case json.Number:
+		f, _ := x.Float64()
+		return f
+	default:
+		return 0
+	}
+}
+
+// Write sets a variable (creating it if needed), persists, and fans the new value
+// out to all subscribers.
+func (s *Source) Write(_ context.Context, signal string, value any) error {
+	v := toFloat64(value)
+
+	s.mu.Lock()
+	now := time.Now()
+	s.vars[signal] = &variable{value: v, ts: now}
+	s.saveLocked()
+	subs := make([]chan<- datasource.Value, 0, len(s.subs[signal]))
+	for _, ch := range s.subs[signal] {
+		subs = append(subs, ch)
+	}
+	s.mu.Unlock()
+
+	upd := datasource.Value{Timestamp: now, Data: v, Quality: datasource.QualityGood}
+	for _, ch := range subs {
+		select {
+		case ch <- upd:
+		default:
+		}
+	}
+	return nil
+}
+
+// History is not supported.
+func (s *Source) History(_ context.Context, _ string, _, _ time.Time, _ int) ([]datasource.Value, error) {
+	return nil, datasource.ErrHistoryUnavailable
+}

internal/datasource/servervar/servervar_test.go

@@ -0,0 +1,74 @@
+package servervar
+
+import (
+	"context"
+	"testing"
+	"time"
+
+	"github.com/uopi/uopi/internal/datasource"
+)
+
+func TestWriteSubscribePersist(t *testing.T) {
+	dir := t.TempDir()
+	s, err := New(dir)
+	if err != nil {
+		t.Fatalf("New: %v", err)
+	}
+	ctx := context.Background()
+
+	if err := s.Write(ctx, "seq_state", 3.0); err != nil {
+		t.Fatalf("Write: %v", err)
+	}
+
+	// Subscribe should deliver the current value immediately.
+	ch := make(chan datasource.Value, 4)
+	cancel, err := s.Subscribe(ctx, "seq_state", ch)
+	if err != nil {
+		t.Fatalf("Subscribe: %v", err)
+	}
+	defer cancel()
+	select {
+	case v := <-ch:
+		if got := v.Data.(float64); got != 3.0 {
+			t.Fatalf("initial value = %v, want 3", got)
+		}
+	case <-time.After(time.Second):
+		t.Fatal("no initial value delivered")
+	}
+
+	// A later write fans out to the subscriber.
+	if err := s.Write(ctx, "seq_state", 7.0); err != nil {
+		t.Fatalf("Write 2: %v", err)
+	}
+	select {
+	case v := <-ch:
+		if got := v.Data.(float64); got != 7.0 {
+			t.Fatalf("updated value = %v, want 7", got)
+		}
+	case <-time.After(time.Second):
+		t.Fatal("no update delivered")
+	}
+
+	// ListSignals reports the variable.
+	sigs, err := s.ListSignals(ctx)
+	if err != nil || len(sigs) != 1 || sigs[0].Name != "seq_state" {
+		t.Fatalf("ListSignals = %+v, err %v", sigs, err)
+	}
+
+	// A fresh store over the same dir recovers the last value.
+	s2, err := New(dir)
+	if err != nil {
+		t.Fatalf("reopen: %v", err)
+	}
+	ch2 := make(chan datasource.Value, 1)
+	cancel2, _ := s2.Subscribe(ctx, "seq_state", ch2)
+	defer cancel2()
+	select {
+	case v := <-ch2:
+		if got := v.Data.(float64); got != 7.0 {
+			t.Fatalf("persisted value = %v, want 7", got)
+		}
+	case <-time.After(time.Second):
+		t.Fatal("persisted value not delivered")
+	}
+}

internal/datasource/synthetic/definition.go

@@ -9,6 +9,7 @@ type SignalDef struct {
 	Signal   string        `json:"signal"`  // upstream signal name (or "" for constant)
 	Inputs   []InputRef    `json:"inputs"`  // alternative multi-input format
 	Pipeline []NodeDef     `json:"pipeline"` // ordered list of DSP nodes
+	Graph    *Graph        `json:"graph,omitempty"` // DAG form (preferred when present)
 	Meta     MetaOverride  `json:"meta"`    // optional metadata overrides
 
 	// Visibility controls who sees this signal in the signal tree:
@@ -34,6 +35,37 @@ type NodeDef struct {
 	Params map[string]any `json:"params,omitempty"`
 }
 
+// Graph is the DAG form of a synthetic signal: a set of nodes (sources, ops and
+// one output) wired together by explicit per-node ordered input lists. It
+// supersedes the linear Inputs+Pipeline form: when SignalDef.Graph is set it is
+// authoritative; otherwise the legacy linear fields are converted into an
+// equivalent graph at load time (see toGraph).
+type Graph struct {
+	Nodes  []GraphNode `json:"nodes"`
+	Output string      `json:"output"` // id of the output node
+}
+
+// GraphNode is one node in a Graph.
+//
+//	kind=="source": carries DS+Signal; has no Inputs (a graph root).
+//	kind=="op":     carries Op + Params; Inputs lists upstream node IDs in the
+//	                order the op receives them (input 0, 1, … e.g. a−b, a÷b).
+//	kind=="output": Inputs has a single upstream node whose value is the result.
+//
+// X/Y are the editor layout coordinates, persisted so a reloaded graph keeps its
+// shape; they have no effect on evaluation.
+type GraphNode struct {
+	ID     string         `json:"id"`
+	Kind   string         `json:"kind"`
+	Op     string         `json:"op,omitempty"`
+	Params map[string]any `json:"params,omitempty"`
+	DS     string         `json:"ds,omitempty"`
+	Signal string         `json:"signal,omitempty"`
+	Inputs []string       `json:"inputs,omitempty"`
+	X      float64        `json:"x,omitempty"`
+	Y      float64        `json:"y,omitempty"`
+}
+
 // MetaOverride allows the synthetic signal to override display metadata.
 type MetaOverride struct {
 	Unit        string  `json:"unit,omitempty"`

internal/datasource/synthetic/dsp_bridge.go

@@ -38,21 +38,32 @@ func stringParam(params map[string]any, key string) string {
 	return s
 }
 
-// BuildPipeline converts a []NodeDef (from JSON) into a []dsp.Node ready for
+// stringSliceParam extracts a []string from params; JSON arrays decode to []any,
-// execution. JSON numbers are float64, so all numeric params are handled as
+// so each element is coerced via its string value. Returns nil if missing.
-// float64 regardless of the final type needed.
+func stringSliceParam(params map[string]any, key string) []string {
-func BuildPipeline(defs []NodeDef) ([]dsp.Node, error) {
+	if params == nil {
-	nodes := make([]dsp.Node, 0, len(defs))
+		return nil
-	for i, d := range defs {
-		n, err := buildNode(d)
-		if err != nil {
-			return nil, fmt.Errorf("pipeline node %d (%q): %w", i, d.Type, err)
-		}
-		nodes = append(nodes, n)
 	}
-	return nodes, nil
+	v, ok := params[key]
+	if !ok {
+		return nil
+	}
+	arr, ok := v.([]any)
+	if !ok {
+		return nil
+	}
+	out := make([]string, 0, len(arr))
+	for _, e := range arr {
+		if s, ok := e.(string); ok && s != "" {
+			out = append(out, s)
+		}
+	}
+	return out
 }
 
+// buildNode converts a single NodeDef (from JSON) into a dsp.Node ready for
+// execution. JSON numbers are float64, so all numeric params are handled as
+// float64 regardless of the final type needed.
 func buildNode(d NodeDef) (dsp.Node, error) {
 	p := d.Params
 	switch d.Type {
@@ -100,7 +111,7 @@ func buildNode(d NodeDef) (dsp.Node, error) {
 		}, nil
 
 	case "expr":
-		return &dsp.ExprNode{Expr: stringParam(p, "expr")}, nil
+		return &dsp.ExprNode{Expr: stringParam(p, "expr"), Vars: stringSliceParam(p, "vars")}, nil
 
 	case "lowpass":
 		order := int(floatParam(p, "order"))
@@ -113,7 +124,7 @@ func buildNode(d NodeDef) (dsp.Node, error) {
 		}, nil
 
 	case "lua":
-		return &dsp.LuaNode{Script: stringParam(p, "script")}, nil
+		return &dsp.LuaNode{Script: stringParam(p, "script"), Vars: stringSliceParam(p, "vars")}, nil
 
 	default:
 		return nil, fmt.Errorf("unknown node type %q", d.Type)

internal/datasource/synthetic/graph.go

@@ -0,0 +1,199 @@
+package synthetic
+
+import (
+	"errors"
+	"fmt"
+
+	"github.com/uopi/uopi/internal/broker"
+	"github.com/uopi/uopi/internal/dsp"
+)
+
+// runtimeGraph is the executable form of a synthetic signal's DAG. Nodes are
+// held in topological order so a single forward pass computes every value with
+// each node's inputs already resolved. Op-node state maps persist across
+// evaluations (for stateful nodes like moving_average / lua).
+type runtimeGraph struct {
+	order    []*rtNode  // topological order (sources first, output last)
+	sources  []rtSource // source nodes, in topological order
+	outputID string     // id of the output node
+}
+
+type rtNode struct {
+	id     string
+	kind   string         // source | op | output
+	op     dsp.Node       // set for kind==op
+	state  map[string]any // persistent per-node state (op only)
+	inputs []string       // upstream node ids, in input order
+}
+
+type rtSource struct {
+	id  string
+	ref broker.SignalRef
+}
+
+// sourceRefs returns the broker references for every source node, in a stable
+// order matching rg.sources.
+func (rg *runtimeGraph) sourceRefs() []broker.SignalRef {
+	refs := make([]broker.SignalRef, len(rg.sources))
+	for i, s := range rg.sources {
+		refs[i] = s.ref
+	}
+	return refs
+}
+
+// eval computes the output value given the latest value for each source node
+// (keyed by source node id). Nodes are visited in topological order so every
+// input is already present in vals by the time a node is processed.
+func (rg *runtimeGraph) eval(sourceVals map[string]float64) (float64, error) {
+	vals := make(map[string]float64, len(rg.order))
+	for id, v := range sourceVals {
+		vals[id] = v
+	}
+	for _, n := range rg.order {
+		switch n.kind {
+		case "op":
+			in := make([]float64, len(n.inputs))
+			for i, id := range n.inputs {
+				in[i] = vals[id]
+			}
+			r, err := n.op.Process(in, n.state)
+			if err != nil {
+				return 0, fmt.Errorf("node %s (%s): %w", n.id, n.op.Type(), err)
+			}
+			vals[n.id] = r
+		case "output":
+			if len(n.inputs) > 0 {
+				vals[n.id] = vals[n.inputs[0]]
+			}
+		}
+	}
+	return vals[rg.outputID], nil
+}
+
+// compileGraph converts a SignalDef into an executable runtimeGraph. When the
+// def carries an explicit Graph it is used directly; otherwise the legacy
+// Inputs+Pipeline form is converted to an equivalent linear graph (see toGraph).
+func compileGraph(def SignalDef) (*runtimeGraph, error) {
+	g := toGraph(def)
+	if g == nil || len(g.Nodes) == 0 {
+		return &runtimeGraph{}, nil
+	}
+	order, err := topoOrder(g)
+	if err != nil {
+		return nil, err
+	}
+	rg := &runtimeGraph{outputID: g.Output}
+	for _, gn := range order {
+		switch gn.Kind {
+		case "source":
+			rg.sources = append(rg.sources, rtSource{id: gn.ID, ref: broker.SignalRef{DS: gn.DS, Name: gn.Signal}})
+		case "op":
+			node, err := buildNode(NodeDef{Type: gn.Op, Params: gn.Params})
+			if err != nil {
+				return nil, fmt.Errorf("node %q: %w", gn.ID, err)
+			}
+			rg.order = append(rg.order, &rtNode{id: gn.ID, kind: "op", op: node, state: map[string]any{}, inputs: gn.Inputs})
+		case "output":
+			rg.outputID = gn.ID
+			rg.order = append(rg.order, &rtNode{id: gn.ID, kind: "output", inputs: gn.Inputs})
+		default:
+			return nil, fmt.Errorf("node %q: unknown kind %q", gn.ID, gn.Kind)
+		}
+	}
+	return rg, nil
+}
+
+// topoOrder returns the graph's nodes in a topological (dependency-first) order,
+// treating each node's Inputs as its predecessors. It errors on dangling input
+// references or cycles.
+func topoOrder(g *Graph) ([]GraphNode, error) {
+	byID := make(map[string]GraphNode, len(g.Nodes))
+	for _, n := range g.Nodes {
+		byID[n.ID] = n
+	}
+	indeg := make(map[string]int, len(g.Nodes))
+	succ := make(map[string][]string, len(g.Nodes))
+	for _, n := range g.Nodes {
+		if _, ok := indeg[n.ID]; !ok {
+			indeg[n.ID] = 0
+		}
+		for _, in := range n.Inputs {
+			if _, ok := byID[in]; !ok {
+				return nil, fmt.Errorf("node %q references unknown input %q", n.ID, in)
+			}
+			indeg[n.ID]++
+			succ[in] = append(succ[in], n.ID)
+		}
+	}
+	// Seed the queue with roots, preserving the node slice order for determinism.
+	queue := make([]string, 0, len(g.Nodes))
+	for _, n := range g.Nodes {
+		if indeg[n.ID] == 0 {
+			queue = append(queue, n.ID)
+		}
+	}
+	order := make([]GraphNode, 0, len(g.Nodes))
+	for len(queue) > 0 {
+		id := queue[0]
+		queue = queue[1:]
+		order = append(order, byID[id])
+		for _, s := range succ[id] {
+			indeg[s]--
+			if indeg[s] == 0 {
+				queue = append(queue, s)
+			}
+		}
+	}
+	if len(order) != len(g.Nodes) {
+		return nil, errors.New("graph contains a cycle")
+	}
+	return order, nil
+}
+
+// toGraph returns the DAG for a SignalDef. If def.Graph is set it is returned
+// as-is. Otherwise the legacy linear form is converted: each input signal
+// becomes a source node, the pipeline becomes a chain of op nodes (the first op
+// receiving every source, each later op the previous op's output), terminated by
+// an output node. With no pipeline the output takes the first source directly,
+// matching the old runPipeline behaviour.
+func toGraph(def SignalDef) *Graph {
+	if def.Graph != nil && len(def.Graph.Nodes) > 0 {
+		return def.Graph
+	}
+
+	inputs := def.Inputs
+	if len(inputs) == 0 && def.DS != "" && def.Signal != "" {
+		inputs = []InputRef{{DS: def.DS, Signal: def.Signal}}
+	}
+
+	nodes := make([]GraphNode, 0, len(inputs)+len(def.Pipeline)+1)
+	srcIDs := make([]string, 0, len(inputs))
+	for i, inp := range inputs {
+		id := fmt.Sprintf("s%d", i)
+		nodes = append(nodes, GraphNode{ID: id, Kind: "source", DS: inp.DS, Signal: inp.Signal})
+		srcIDs = append(srcIDs, id)
+	}
+
+	opIDs := make([]string, 0, len(def.Pipeline))
+	for i, nd := range def.Pipeline {
+		id := fmt.Sprintf("p%d", i)
+		var ins []string
+		if i == 0 {
+			ins = srcIDs
+		} else {
+			ins = []string{opIDs[i-1]}
+		}
+		nodes = append(nodes, GraphNode{ID: id, Kind: "op", Op: nd.Type, Params: nd.Params, Inputs: ins})
+		opIDs = append(opIDs, id)
+	}
+
+	var outInputs []string
+	if len(opIDs) > 0 {
+		outInputs = []string{opIDs[len(opIDs)-1]}
+	} else if len(srcIDs) > 0 {
+		outInputs = []string{srcIDs[0]}
+	}
+	nodes = append(nodes, GraphNode{ID: "out", Kind: "output", Inputs: outInputs})
+
+	return &Graph{Nodes: nodes, Output: "out"}
+}

internal/datasource/synthetic/graph_test.go

@@ -0,0 +1,130 @@
+package synthetic
+
+import (
+	"math"
+	"testing"
+)
+
+// evalDef compiles a SignalDef and evaluates it against per-source values keyed
+// by source node id.
+func evalDef(t *testing.T, def SignalDef, srcVals map[string]float64) float64 {
+	t.Helper()
+	rg, err := compileGraph(def)
+	if err != nil {
+		t.Fatalf("compileGraph: %v", err)
+	}
+	out, err := rg.eval(srcVals)
+	if err != nil {
+		t.Fatalf("eval: %v", err)
+	}
+	return out
+}
+
+// TestGraphMultiInputDAG verifies that an intermediate op can take two
+// independently-wired sources — the capability the old linear pipeline lacked.
+func TestGraphMultiInputDAG(t *testing.T) {
+	def := SignalDef{
+		Name: "diff",
+		Graph: &Graph{
+			Output: "out",
+			Nodes: []GraphNode{
+				{ID: "a", Kind: "source", DS: "x", Signal: "left"},
+				{ID: "b", Kind: "source", DS: "x", Signal: "right"},
+				{ID: "sub", Kind: "op", Op: "subtract", Inputs: []string{"a", "b"}},
+				{ID: "out", Kind: "output", Inputs: []string{"sub"}},
+			},
+		},
+	}
+	got := evalDef(t, def, map[string]float64{"a": 10, "b": 3})
+	if got != 7 {
+		t.Errorf("subtract DAG: want 7, got %v", got)
+	}
+}
+
+// TestGraphExprNamedInputs verifies expr nodes bind arbitrary named inputs in
+// wired order.
+func TestGraphExprNamedInputs(t *testing.T) {
+	def := SignalDef{
+		Name: "formula",
+		Graph: &Graph{
+			Output: "out",
+			Nodes: []GraphNode{
+				{ID: "a", Kind: "source", DS: "x", Signal: "p"},
+				{ID: "b", Kind: "source", DS: "x", Signal: "q"},
+				{ID: "e", Kind: "op", Op: "expr", Inputs: []string{"a", "b"},
+					Params: map[string]any{"expr": "price * qty", "vars": []any{"price", "qty"}}},
+				{ID: "out", Kind: "output", Inputs: []string{"e"}},
+			},
+		},
+	}
+	got := evalDef(t, def, map[string]float64{"a": 4, "b": 2.5})
+	if math.Abs(got-10) > 1e-9 {
+		t.Errorf("expr named inputs: want 10, got %v", got)
+	}
+}
+
+// TestGraphFanInToExpr exercises a non-trivial DAG: two ops feeding one expr.
+func TestGraphFanInToExpr(t *testing.T) {
+	def := SignalDef{
+		Name: "combo",
+		Graph: &Graph{
+			Output: "out",
+			Nodes: []GraphNode{
+				{ID: "a", Kind: "source", DS: "x", Signal: "p"},
+				{ID: "b", Kind: "source", DS: "x", Signal: "q"},
+				{ID: "g", Kind: "op", Op: "gain", Inputs: []string{"a"}, Params: map[string]any{"gain": 2.0}},
+				{ID: "o", Kind: "op", Op: "offset", Inputs: []string{"b"}, Params: map[string]any{"offset": 1.0}},
+				{ID: "e", Kind: "op", Op: "expr", Inputs: []string{"g", "o"}, Params: map[string]any{"expr": "a + b"}},
+				{ID: "out", Kind: "output", Inputs: []string{"e"}},
+			},
+		},
+	}
+	// g = 5*2 = 10 ; o = 4+1 = 5 ; a+b = 15
+	got := evalDef(t, def, map[string]float64{"a": 5, "b": 4})
+	if math.Abs(got-15) > 1e-9 {
+		t.Errorf("fan-in DAG: want 15, got %v", got)
+	}
+}
+
+// TestGraphLegacyConversion verifies the linear Inputs+Pipeline form still
+// evaluates correctly via the graph runtime.
+func TestGraphLegacyConversion(t *testing.T) {
+	def := SignalDef{
+		Name:     "legacy",
+		DS:       "x",
+		Signal:   "p",
+		Pipeline: []NodeDef{{Type: "gain", Params: map[string]any{"gain": 3.0}}},
+	}
+	rg, err := compileGraph(def)
+	if err != nil {
+		t.Fatalf("compileGraph: %v", err)
+	}
+	if len(rg.sources) != 1 {
+		t.Fatalf("want 1 source, got %d", len(rg.sources))
+	}
+	got, err := rg.eval(map[string]float64{rg.sources[0].id: 4})
+	if err != nil {
+		t.Fatalf("eval: %v", err)
+	}
+	if got != 12 {
+		t.Errorf("legacy gain: want 12, got %v", got)
+	}
+}
+
+// TestGraphCycleRejected ensures a cyclic graph is refused at compile time.
+func TestGraphCycleRejected(t *testing.T) {
+	def := SignalDef{
+		Name: "cyclic",
+		Graph: &Graph{
+			Output: "out",
+			Nodes: []GraphNode{
+				{ID: "a", Kind: "op", Op: "gain", Inputs: []string{"b"}, Params: map[string]any{"gain": 1.0}},
+				{ID: "b", Kind: "op", Op: "gain", Inputs: []string{"a"}, Params: map[string]any{"gain": 1.0}},
+				{ID: "out", Kind: "output", Inputs: []string{"a"}},
+			},
+		},
+	}
+	if _, err := compileGraph(def); err == nil {
+		t.Error("expected cycle to be rejected")
+	}
+}

internal/datasource/synthetic/synthetic.go

@@ -13,16 +13,14 @@ import (
 
 	"github.com/uopi/uopi/internal/broker"
 	"github.com/uopi/uopi/internal/datasource"
-	"github.com/uopi/uopi/internal/dsp"
 )
 
 const definitionsFile = "synthetic.json"
 
 // signalState holds everything needed to run one synthetic signal.
 type signalState struct {
-	def    SignalDef
+	def SignalDef
-	nodes  []dsp.Node
+	rg  *runtimeGraph // compiled DAG; op-node state persists across evaluations
-	states []map[string]any // one map per node, persistent across calls
 
 	// cancel stops the goroutine driving this signal.
 	cancel context.CancelFunc
@@ -123,19 +121,25 @@ func (s *Synthetic) Subscribe(ctx context.Context, signal string, ch chan<- data
 		return nil, datasource.ErrNotFound
 	}
 
-	// Collect the upstream references for this signal.
+	// Collect the source node references for this signal's DAG.
-	refs := upstreamRefs(st.def)
+	refs := st.rg.sourceRefs()
 	if len(refs) == 0 {
 		return nil, fmt.Errorf("synthetic: signal %q has no upstream inputs", signal)
 	}
+	// Source node ids, index-aligned with refs, so updates map to graph inputs.
+	srcIDs := make([]string, len(st.rg.sources))
+	for i, s := range st.rg.sources {
+		srcIDs[i] = s.id
+	}
 
 	ctx, cancel := context.WithCancel(ctx)
 
 	go func() {
 		defer cancel()
 
-		// Latest value per upstream input index.
+		// Latest value and timestamp per source node id.
-		latest := make([]float64, len(refs))
+		latest := make(map[string]float64, len(refs))
+		latestTs := make([]time.Time, len(refs))
 		ready := make([]bool, len(refs))
 
 		// Subscribe to every upstream ref via the broker.
@@ -184,7 +188,8 @@ func (s *Synthetic) Subscribe(ctx context.Context, signal string, ch chan<- data
 				return
 
 			case upd := <-updateCh:
-				latest[upd.idx] = upd.val
+				latest[srcIDs[upd.idx]] = upd.val
+				latestTs[upd.idx] = upd.ts
 				ready[upd.idx] = true
 
 				// Only compute once we have at least one value for every input.
@@ -199,7 +204,19 @@ func (s *Synthetic) Subscribe(ctx context.Context, signal string, ch chan<- data
 					continue
 				}
 
-				// Run the pipeline.
+				// The output is computed from the latest value of every input, so
+				// its timestamp is the most recent contributing sample time. Using
+				// the triggering update's timestamp instead would drag the output
+				// back in time whenever a slow/stale input fired, producing
+				// non-monotonic or duplicated timestamps on plots.
+				outTs := latestTs[0]
+				for _, ts := range latestTs[1:] {
+					if ts.After(outTs) {
+						outTs = ts
+					}
+				}
+
+				// Evaluate the DAG.
 				s.mu.RLock()
 				cur, stillExists := s.signals[signal]
 				s.mu.RUnlock()
@@ -207,14 +224,14 @@ func (s *Synthetic) Subscribe(ctx context.Context, signal string, ch chan<- data
 					return
 				}
 
-				result, err := runPipeline(cur.nodes, cur.states, latest)
+				result, err := cur.rg.eval(latest)
 				if err != nil {
 					s.log.Warn("synthetic: pipeline error", "signal", signal, "err", err)
 					continue
 				}
 
 				v := datasource.Value{
-					Timestamp: upd.ts,
+					Timestamp: outTs,
 					Data:      result,
 					Quality:   datasource.QualityGood,
 				}
@@ -246,9 +263,9 @@ func (s *Synthetic) AddSignal(def SignalDef) error {
 		return errors.New("signal name must not be empty")
 	}
 
-	nodes, err := BuildPipeline(def.Pipeline)
+	rg, err := compileGraph(def)
 	if err != nil {
-		return fmt.Errorf("build pipeline: %w", err)
+		return fmt.Errorf("compile graph: %w", err)
 	}
 
 	s.mu.Lock()
@@ -257,16 +274,7 @@ func (s *Synthetic) AddSignal(def SignalDef) error {
 		return fmt.Errorf("signal %q already exists", def.Name)
 	}
 
-	states := make([]map[string]any, len(nodes))
+	st := &signalState{def: def, rg: rg}
-	for i := range states {
-		states[i] = make(map[string]any)
-	}
-
-	st := &signalState{
-		def:    def,
-		nodes:  nodes,
-		states: states,
-	}
 	s.signals[def.Name] = st
 	s.mu.Unlock()
 
@@ -320,14 +328,9 @@ func (s *Synthetic) UpdateSignal(def SignalDef) error {
 		return errors.New("signal name must not be empty")
 	}
 
-	nodes, err := BuildPipeline(def.Pipeline)
+	rg, err := compileGraph(def)
 	if err != nil {
-		return fmt.Errorf("build pipeline: %w", err)
+		return fmt.Errorf("compile graph: %w", err)
-	}
-
-	states := make([]map[string]any, len(nodes))
-	for i := range states {
-		states[i] = make(map[string]any)
 	}
 
 	s.mu.Lock()
@@ -339,7 +342,7 @@ func (s *Synthetic) UpdateSignal(def SignalDef) error {
 	if old.cancel != nil {
 		old.cancel()
 	}
-	s.signals[def.Name] = &signalState{def: def, nodes: nodes, states: states}
+	s.signals[def.Name] = &signalState{def: def, rg: rg}
 	s.mu.Unlock()
 
 	if err := s.saveDefs(); err != nil {
@@ -402,73 +405,22 @@ func (s *Synthetic) saveDefs() error {
 	return os.WriteFile(s.defsFilePath(), data, 0o644)
 }
 
-// startSignal builds the pipeline for def and registers the signalState.
+// startSignal compiles the DAG for def and registers the signalState.
 // The actual goroutines are started lazily by Subscribe.
 func (s *Synthetic) startSignal(def SignalDef) error {
-	nodes, err := BuildPipeline(def.Pipeline)
+	rg, err := compileGraph(def)
 	if err != nil {
-		return fmt.Errorf("build pipeline for %q: %w", def.Name, err)
+		return fmt.Errorf("compile graph for %q: %w", def.Name, err)
-	}
-
-	states := make([]map[string]any, len(nodes))
-	for i := range states {
-		states[i] = make(map[string]any)
 	}
 
 	s.mu.Lock()
-	s.signals[def.Name] = &signalState{
+	s.signals[def.Name] = &signalState{def: def, rg: rg}
-		def:    def,
-		nodes:  nodes,
-		states: states,
-	}
 	s.mu.Unlock()
 
 	s.log.Info("synthetic: signal registered", "name", def.Name)
 	return nil
 }
 
-// runPipeline executes all nodes in sequence. The output of node N becomes
-// input[0] of node N+1. For the first node, inputs is the full upstream slice.
-func runPipeline(nodes []dsp.Node, states []map[string]any, inputs []float64) (float64, error) {
-	if len(nodes) == 0 {
-		if len(inputs) == 0 {
-			return 0, nil
-		}
-		return inputs[0], nil
-	}
-
-	// First node receives all upstream inputs.
-	cur := inputs
-	var result float64
-	var err error
-
-	for i, node := range nodes {
-		result, err = node.Process(cur, states[i])
-		if err != nil {
-			return 0, fmt.Errorf("node %d (%s): %w", i, node.Type(), err)
-		}
-		// Subsequent nodes receive only the single output of the previous node.
-		cur = []float64{result}
-	}
-	return result, nil
-}
-
-// upstreamRefs returns the broker.SignalRef list for a SignalDef.
-// If Inputs is set, those take precedence; otherwise DS+Signal is used.
-func upstreamRefs(def SignalDef) []broker.SignalRef {
-	if len(def.Inputs) > 0 {
-		refs := make([]broker.SignalRef, len(def.Inputs))
-		for i, inp := range def.Inputs {
-			refs[i] = broker.SignalRef{DS: inp.DS, Name: inp.Signal}
-		}
-		return refs
-	}
-	if def.DS != "" && def.Signal != "" {
-		return []broker.SignalRef{{DS: def.DS, Name: def.Signal}}
-	}
-	return nil
-}
-
 // defToMetadata converts a SignalDef into a datasource.Metadata.
 func defToMetadata(def SignalDef) datasource.Metadata {
 	return datasource.Metadata{

internal/datasource/synthetic/timestamp_test.go

@@ -0,0 +1,154 @@
+package synthetic
+
+import (
+	"context"
+	"log/slog"
+	"os"
+	"testing"
+	"time"
+
+	"github.com/uopi/uopi/internal/broker"
+	"github.com/uopi/uopi/internal/datasource"
+)
+
+// seqSource is a test DataSource that emits a fixed sequence of values, each
+// carrying its own timestamp, so tests can control upstream sample times.
+type seqSource struct {
+	name string
+	seq  []datasource.Value
+}
+
+func (s *seqSource) Name() string                                          { return s.name }
+func (s *seqSource) Connect(context.Context) error                         { return nil }
+func (s *seqSource) ListSignals(context.Context) ([]datasource.Metadata, error) { return nil, nil }
+func (s *seqSource) GetMetadata(context.Context, string) (datasource.Metadata, error) {
+	return datasource.Metadata{Name: "x", Type: datasource.TypeFloat64}, nil
+}
+func (s *seqSource) Write(context.Context, string, any) error { return datasource.ErrNotWritable }
+func (s *seqSource) History(context.Context, string, time.Time, time.Time, int) ([]datasource.Value, error) {
+	return nil, datasource.ErrHistoryUnavailable
+}
+func (s *seqSource) Subscribe(ctx context.Context, _ string, ch chan<- datasource.Value) (datasource.CancelFunc, error) {
+	go func() {
+		for _, v := range s.seq {
+			select {
+			case ch <- v:
+			case <-ctx.Done():
+				return
+			}
+			time.Sleep(8 * time.Millisecond)
+		}
+	}()
+	return func() {}, nil
+}
+
+// TestSubscribePreservesUpstreamTimestamp verifies a single-source synthetic
+// emits each computed value with the upstream sample's timestamp.
+func TestSubscribePreservesUpstreamTimestamp(t *testing.T) {
+	log := slog.New(slog.NewTextHandler(os.Stderr, nil))
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	base := time.Date(2026, 6, 19, 10, 0, 0, 0, time.UTC)
+	src := &seqSource{name: "src", seq: []datasource.Value{
+		{Timestamp: base.Add(1 * time.Second), Data: 1.0, Quality: datasource.QualityGood},
+		{Timestamp: base.Add(2 * time.Second), Data: 2.0, Quality: datasource.QualityGood},
+		{Timestamp: base.Add(3 * time.Second), Data: 3.0, Quality: datasource.QualityGood},
+	}}
+
+	brk := broker.New(ctx, log)
+	brk.Register(src)
+	syn := New(t.TempDir(), brk, log)
+	if err := syn.Connect(ctx); err != nil {
+		t.Fatal(err)
+	}
+	if err := syn.AddSignal(SignalDef{
+		Name: "g", DS: "src", Signal: "x",
+		Pipeline: []NodeDef{{Type: "gain", Params: map[string]any{"gain": 10.0}}},
+	}); err != nil {
+		t.Fatal(err)
+	}
+
+	ch := make(chan datasource.Value, 8)
+	if _, err := syn.Subscribe(ctx, "g", ch); err != nil {
+		t.Fatal(err)
+	}
+
+	want := []time.Time{base.Add(1 * time.Second), base.Add(2 * time.Second), base.Add(3 * time.Second)}
+	for i, w := range want {
+		select {
+		case v := <-ch:
+			if !v.Timestamp.Equal(w) {
+				t.Errorf("emit #%d timestamp: want %s, got %s", i, w, v.Timestamp)
+			}
+		case <-time.After(2 * time.Second):
+			t.Fatalf("timeout waiting for emit #%d", i)
+		}
+	}
+}
+
+// TestSubscribeMultiSourceUsesLatestTimestamp verifies that a synthetic combining
+// two independent sources stamps each output with the MOST RECENT contributing
+// sample time — not the timestamp of whichever source happened to trigger the
+// computation. A slow source carrying a stale timestamp must not drag the output
+// backwards in time (which previously produced wrong/non-monotonic plot points).
+func TestSubscribeMultiSourceUsesLatestTimestamp(t *testing.T) {
+	log := slog.New(slog.NewTextHandler(os.Stderr, nil))
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	now := time.Date(2026, 6, 19, 12, 0, 0, 0, time.UTC)
+	// Fast source A with current timestamps.
+	a := &seqSource{name: "A", seq: []datasource.Value{
+		{Timestamp: now.Add(10 * time.Second), Data: 1.0, Quality: datasource.QualityGood},
+		{Timestamp: now.Add(11 * time.Second), Data: 2.0, Quality: datasource.QualityGood},
+		{Timestamp: now.Add(12 * time.Second), Data: 3.0, Quality: datasource.QualityGood},
+		{Timestamp: now.Add(13 * time.Second), Data: 4.0, Quality: datasource.QualityGood},
+	}}
+	// Slow source B: a single sample with a much older timestamp.
+	b := &seqSource{name: "B", seq: []datasource.Value{
+		{Timestamp: now.Add(1 * time.Second), Data: 100.0, Quality: datasource.QualityGood},
+	}}
+
+	brk := broker.New(ctx, log)
+	brk.Register(a)
+	brk.Register(b)
+	syn := New(t.TempDir(), brk, log)
+	if err := syn.Connect(ctx); err != nil {
+		t.Fatal(err)
+	}
+	if err := syn.AddSignal(SignalDef{
+		Name: "diff",
+		Graph: &Graph{Output: "out", Nodes: []GraphNode{
+			{ID: "sa", Kind: "source", DS: "A", Signal: "x"},
+			{ID: "sb", Kind: "source", DS: "B", Signal: "x"},
+			{ID: "sub", Kind: "op", Op: "subtract", Inputs: []string{"sa", "sb"}},
+			{ID: "out", Kind: "output", Inputs: []string{"sub"}},
+		}},
+	}); err != nil {
+		t.Fatal(err)
+	}
+
+	ch := make(chan datasource.Value, 16)
+	if _, err := syn.Subscribe(ctx, "diff", ch); err != nil {
+		t.Fatal(err)
+	}
+
+	var last time.Time
+	for i := 0; i < 4; i++ {
+		select {
+		case v := <-ch:
+			// The stale source-B timestamp (t=1s) must never be used: every output
+			// is stamped with the newest input time, so emits stay monotonic.
+			if v.Timestamp.Equal(now.Add(1 * time.Second)) {
+				t.Errorf("emit #%d used the stale source-B timestamp %s", i, v.Timestamp)
+			}
+			if !last.IsZero() && v.Timestamp.Before(last) {
+				t.Errorf("emit #%d went backwards: %s before previous %s", i, v.Timestamp, last)
+			}
+			last = v.Timestamp
+		case <-time.After(2 * time.Second):
+			t.Fatalf("timeout waiting for emit #%d", i)
+		}
+	}
+}

internal/dsp/nodes.go

@@ -277,16 +277,28 @@ func (n *ThresholdNode) Process(inputs []float64, _ map[string]any) (float64, er
 
 // ── ExprNode ──────────────────────────────────────────────────────────────────
 
-// ExprNode evaluates a simple arithmetic expression with variables a, b, c, d
+// ExprNode evaluates a simple arithmetic expression. Inputs are bound to named
-// bound to inputs[0..3]. It uses a hand-written recursive descent parser.
+// variables: Vars[i] -> inputs[i]. When Vars is empty it defaults to a, b, c, d
+// (bound to inputs[0..3]) for backward compatibility. It uses a hand-written
+// recursive descent parser.
 type ExprNode struct {
 	Expr string
+	Vars []string
+}
+
+// defaultVarNames returns the variable names for an expr/lua node: the explicit
+// list when set, otherwise the legacy a,b,c,d.
+func defaultVarNames(vars []string) []string {
+	if len(vars) > 0 {
+		return vars
+	}
+	return []string{"a", "b", "c", "d"}
 }
 
 func (n *ExprNode) Type() string { return "expr" }
 func (n *ExprNode) Process(inputs []float64, _ map[string]any) (float64, error) {
 	vars := map[string]float64{}
-	names := []string{"a", "b", "c", "d"}
+	names := defaultVarNames(n.Vars)
 	for i, name := range names {
 		if i < len(inputs) {
 			vars[name] = inputs[i]
@@ -507,13 +519,10 @@ func (p *exprParser) parseCall() (float64, error) {
 			}
 		}
 
-		// Not a function call — must be a single-letter variable.
+		// Not a function call — must be a declared input variable.
-		if len(name) != 1 {
-			return 0, fmt.Errorf("unknown identifier %q (use a–d for variables, or a known function name)", name)
-		}
 		val, ok := p.vars[name]
 		if !ok {
-			return 0, fmt.Errorf("unknown variable %q (allowed: a, b, c, d)", name)
+			return 0, fmt.Errorf("unknown variable %q (declare it as a named input)", name)
 		}
 		return val, nil
 	}
@@ -628,10 +637,12 @@ func (n *LowPassNode) Process(inputs []float64, state map[string]any) (float64,
 // ── LuaNode ───────────────────────────────────────────────────────────────────
 
 // LuaNode runs a Lua script in a sandboxed gopher-lua VM.
-// Inputs are bound to globals a, b, c, d. The script's return value is the output.
+// Inputs are bound to globals named by Vars (Vars[i] -> inputs[i]); when Vars is
+// empty it defaults to a, b, c, d. The script's return value is the output.
 // The os, io, package, and debug libraries are disabled.
 type LuaNode struct {
 	Script string
+	Vars   []string
 }
 
 func (n *LuaNode) Type() string { return "lua" }
@@ -682,7 +693,7 @@ func (n *LuaNode) Process(inputs []float64, state map[string]any) (result float6
 	L.SetTop(0)
 
 	// Bind inputs.
-	names := []string{"a", "b", "c", "d"}
+	names := defaultVarNames(n.Vars)
 	for i, name := range names {
 		if i < len(inputs) {
 			L.SetGlobal(name, lua.LNumber(inputs[i]))

internal/server/dialoghub.go

@@ -0,0 +1,199 @@
+package server
+
+import (
+	"context"
+	"encoding/json"
+	"log/slog"
+	"strconv"
+	"strings"
+	"sync"
+
+	"github.com/uopi/uopi/internal/access"
+	"github.com/uopi/uopi/internal/audit"
+	"github.com/uopi/uopi/internal/broker"
+	"github.com/uopi/uopi/internal/controllogic"
+	"github.com/uopi/uopi/internal/datasource"
+)
+
+// DialogHub fans control-logic dialog requests out to connected WebSocket
+// clients whose identity matches the dialog's user/group filter, and routes
+// input responses back to the dialog's target server variable.
+//
+// It implements controllogic.Notifier; the engine calls Notify when an
+// action.dialog node runs. Input dialogs are remembered as pending so a later
+// dialogResponse can be correlated by id and validated against its recipient
+// filter — this is why panels can write the response target even though direct
+// srv writes are otherwise gated to control-logic editors.
+type DialogHub struct {
+	broker *broker.Broker
+	policy *access.Policy
+	audit  audit.Recorder
+	log    *slog.Logger
+
+	mu      sync.Mutex
+	clients map[*wsClient]struct{}
+	pending map[string]controllogic.Dialog // input dialogs awaiting a response
+}
+
+// NewDialogHub builds an empty hub. rec is never nil after construction.
+func NewDialogHub(brk *broker.Broker, policy *access.Policy, rec audit.Recorder, log *slog.Logger) *DialogHub {
+	if rec == nil {
+		rec = audit.Nop()
+	}
+	return &DialogHub{
+		broker:  brk,
+		policy:  policy,
+		audit:   rec,
+		log:     log,
+		clients: map[*wsClient]struct{}{},
+		pending: map[string]controllogic.Dialog{},
+	}
+}
+
+func (h *DialogHub) add(c *wsClient) {
+	h.mu.Lock()
+	h.clients[c] = struct{}{}
+	h.mu.Unlock()
+}
+
+func (h *DialogHub) remove(c *wsClient) {
+	h.mu.Lock()
+	delete(h.clients, c)
+	h.mu.Unlock()
+}
+
+// dialogOut is the client-bound JSON form of a dialog request.
+type dialogOut struct {
+	Type    string `json:"type"` // always "dialog"
+	ID      string `json:"id"`
+	Kind    string `json:"kind"` // "info" | "error" | "input"
+	Title   string `json:"title,omitempty"`
+	Message string `json:"message,omitempty"`
+}
+
+// Notify implements controllogic.Notifier: serialise the dialog and push it to
+// every connected client matching its user/group filter.
+func (h *DialogHub) Notify(d controllogic.Dialog) {
+	b, err := json.Marshal(dialogOut{
+		Type:    "dialog",
+		ID:      d.ID,
+		Kind:    d.Kind,
+		Title:   d.Title,
+		Message: d.Message,
+	})
+	if err != nil {
+		return
+	}
+
+	h.mu.Lock()
+	if d.Kind == "input" && strings.TrimSpace(d.Target) != "" {
+		h.pending[d.ID] = d
+	}
+	var targets []*wsClient
+	for c := range h.clients {
+		if h.matches(c.user, d) {
+			targets = append(targets, c)
+		}
+	}
+	h.mu.Unlock()
+
+	for _, c := range targets {
+		select {
+		case c.outCh <- b:
+		default:
+		}
+	}
+}
+
+// matches reports whether user is a recipient of d. An empty user+group filter
+// targets everyone; otherwise the user must be named or in a named group.
+func (h *DialogHub) matches(user string, d controllogic.Dialog) bool {
+	if len(d.Users) == 0 && len(d.Groups) == 0 {
+		return true
+	}
+	if h.policy != nil {
+		user = h.policy.ResolveUser(user)
+	}
+	for _, u := range d.Users {
+		if u == user {
+			return true
+		}
+	}
+	if len(d.Groups) > 0 && h.policy != nil {
+		groups := map[string]bool{}
+		for _, g := range h.policy.GroupsOf(user) {
+			groups[g] = true
+		}
+		for _, g := range d.Groups {
+			if groups[g] {
+				return true
+			}
+		}
+	}
+	return false
+}
+
+// cancel drops a pending input dialog without writing (user dismissed it).
+func (h *DialogHub) cancel(id string) {
+	h.mu.Lock()
+	delete(h.pending, id)
+	h.mu.Unlock()
+}
+
+// respond writes an input dialog's response to its target server variable. The
+// dialog must be pending and the responding client must have been a recipient;
+// this gate replaces the usual srv write-permission check for sanctioned
+// control-logic responses.
+func (h *DialogHub) respond(ctx context.Context, c *wsClient, id string, value float64) {
+	h.mu.Lock()
+	d, ok := h.pending[id]
+	if ok {
+		delete(h.pending, id)
+	}
+	h.mu.Unlock()
+	if !ok || !h.matches(c.user, d) {
+		return
+	}
+
+	ds, name, ok := parseDialogTarget(d.Target)
+	if !ok || ds == "local" {
+		return
+	}
+	src, ok := h.broker.Source(ds)
+	if !ok {
+		h.log.Warn("dialog response: unknown data source", "ds", ds, "target", d.Target)
+		return
+	}
+
+	ev := audit.Event{
+		Actor:     c.user,
+		ActorType: audit.ActorUser,
+		Action:    "signal.write",
+		DS:        ds,
+		Signal:    name,
+		Value:     strconv.FormatFloat(value, 'g', -1, 64),
+		Detail:    "control logic dialog response",
+		IP:        c.ip,
+		Outcome:   audit.OutcomeOK,
+	}
+	wctx := datasource.WithUser(ctx, c.user)
+	if err := src.Write(wctx, name, value); err != nil {
+		h.log.Warn("dialog response: write failed", "ds", ds, "signal", name, "err", err)
+		ev.Outcome = audit.OutcomeError
+		ev.Error = err.Error()
+	}
+	h.audit.Record(ev)
+}
+
+// parseDialogTarget splits a "ds:name" dialog target on the first ':'. A bare
+// name (no ':') defaults to the persistent server-variable source "srv".
+func parseDialogTarget(t string) (ds, name string, ok bool) {
+	t = strings.TrimSpace(t)
+	if t == "" {
+		return "", "", false
+	}
+	if i := strings.IndexByte(t, ':'); i >= 0 {
+		return t[:i], t[i+1:], true
+	}
+	return "srv", t, true
+}

internal/server/server.go

@@ -10,6 +10,7 @@ import (
 
 	"github.com/uopi/uopi/internal/access"
 	"github.com/uopi/uopi/internal/api"
+	"github.com/uopi/uopi/internal/audit"
 	"github.com/uopi/uopi/internal/broker"
 	"github.com/uopi/uopi/internal/controllogic"
 	"github.com/uopi/uopi/internal/datasource/synthetic"
@@ -27,7 +28,10 @@ type Server struct {
 
 // New creates the HTTP server, registers all routes, and returns a ready-to-start Server.
 // synth may be nil if the synthetic data source is not enabled.
-func New(addr string, webFS fs.FS, brk *broker.Broker, synth *synthetic.Synthetic, store *storage.Store, policy *access.Policy, acl *panelacl.Store, ctrlLogic *controllogic.Store, ctrlEngine *controllogic.Engine, channelFinderURL, archiverURL, trustedUserHeader string, log *slog.Logger) *Server {
+func New(addr string, webFS fs.FS, brk *broker.Broker, synth *synthetic.Synthetic, store *storage.Store, policy *access.Policy, acl *panelacl.Store, ctrlLogic *controllogic.Store, ctrlEngine *controllogic.Engine, dialogs *DialogHub, rec audit.Recorder, channelFinderURL, archiverURL, trustedUserHeader string, log *slog.Logger) *Server {
+	if rec == nil {
+		rec = audit.Nop()
+	}
 	mux := http.NewServeMux()
 
 	// Health check
@@ -37,7 +41,7 @@ func New(addr string, webFS fs.FS, brk *broker.Broker, synth *synthetic.Syntheti
 	})
 
 	// WebSocket endpoint
-	mux.Handle("/ws", &wsHandler{broker: brk, log: log, userHeader: trustedUserHeader, policy: policy})
+	mux.Handle("/ws", &wsHandler{broker: brk, log: log, userHeader: trustedUserHeader, policy: policy, audit: rec, dialogs: dialogs})
 
 	// Prometheus-format metrics
 	mux.HandleFunc("/metrics", metrics.Handler(brk.ActiveSubscriptions))
@@ -45,7 +49,7 @@ func New(addr string, webFS fs.FS, brk *broker.Broker, synth *synthetic.Syntheti
 	// REST API — registered on a dedicated mux so it can be wrapped with the
 	// access-control middleware (identity resolution + global level enforcement).
 	apiMux := http.NewServeMux()
-	api.New(brk, synth, store, policy, acl, ctrlLogic, ctrlEngine, channelFinderURL, archiverURL, log).Register(apiMux, apiPrefix)
+	api.New(brk, synth, store, policy, acl, ctrlLogic, ctrlEngine, rec, channelFinderURL, archiverURL, log).Register(apiMux, apiPrefix)
 	mux.Handle(apiPrefix+"/", accessMiddleware(policy, trustedUserHeader, apiMux))
 
 	// Embedded frontend — must be last (catch-all)

internal/server/ws.go

@@ -5,7 +5,9 @@ import (
 	"encoding/json"
 	"errors"
 	"log/slog"
+	"net"
 	"net/http"
+	"strconv"
 	"strings"
 	"sync"
 	"time"
@@ -13,6 +15,7 @@ import (
 	"github.com/coder/websocket"
 
 	"github.com/uopi/uopi/internal/access"
+	"github.com/uopi/uopi/internal/audit"
 	"github.com/uopi/uopi/internal/broker"
 	"github.com/uopi/uopi/internal/datasource"
 	"github.com/uopi/uopi/internal/metrics"
@@ -31,6 +34,9 @@ type inMsg struct {
 	Name  string          `json:"name,omitempty"`
 	Value json.RawMessage `json:"value,omitempty"`
 
+	// dialogResponse — id of the control-logic dialog being answered.
+	ID string `json:"id,omitempty"`
+
 	// history
 	Start     time.Time `json:"start"`
 	End       time.Time `json:"end"`
@@ -48,11 +54,13 @@ type outMsg struct {
 	Type string `json:"type"`
 
 	// update
-	DS      string `json:"ds,omitempty"`
+	DS       string `json:"ds,omitempty"`
-	Name    string `json:"name,omitempty"`
+	Name     string `json:"name,omitempty"`
-	TS      string `json:"ts,omitempty"`
+	TS       string `json:"ts,omitempty"`
-	Value   any    `json:"value,omitempty"`
+	Value    any    `json:"value,omitempty"`
-	Quality string `json:"quality,omitempty"`
+	Quality  string `json:"quality,omitempty"`
+	Severity int    `json:"severity,omitempty"` // raw EPICS alarm severity (0=NO_ALARM)
+	Status   int    `json:"status,omitempty"`   // raw EPICS alarm status
 
 	// meta
 	Meta *metaPayload `json:"meta,omitempty"`
@@ -94,6 +102,10 @@ type wsHandler struct {
 	userHeader string
 	// policy enforces the global access level (blacklist) on signal writes.
 	policy *access.Policy
+	// audit records signal writes (never nil; audit.Nop when disabled).
+	audit audit.Recorder
+	// dialogs fans control-logic dialogs to clients and routes responses.
+	dialogs *DialogHub
 }
 
 func (h *wsHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
@@ -103,6 +115,12 @@ func (h *wsHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	if h.userHeader != "" {
 		user = strings.TrimSpace(r.Header.Get(h.userHeader))
 	}
+	// Resolve to the configured default_user when the header is absent so the
+	// session carries a real identity (used for audit + EPICS write attribution).
+	if h.policy != nil {
+		user = h.policy.ResolveUser(user)
+	}
+	clientIP := clientIP(r)
 
 	conn, err := websocket.Accept(w, r, &websocket.AcceptOptions{
 		// Permissive origin check for LAN / SSH-tunnel use; tighten when auth lands.
@@ -118,17 +136,31 @@ func (h *wsHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	ctx, cancel := context.WithCancel(r.Context())
 	defer cancel()
 
+	rec := h.audit
+	if rec == nil {
+		rec = audit.Nop()
+	}
+
 	c := &wsClient{
 		conn:     conn,
 		broker:   h.broker,
 		user:     user,
+		ip:       clientIP,
 		policy:   h.policy,
+		audit:    rec,
+		dialogs:  h.dialogs,
 		outCh:    make(chan []byte, 512),
 		updateCh: make(chan broker.Update, 1024),
 		subs:     make(map[broker.SignalRef]func()),
 		log:      h.log,
 	}
 
+	// Register for control-logic dialog pushes for this client's identity.
+	if h.dialogs != nil {
+		h.dialogs.add(c)
+		defer h.dialogs.remove(c)
+	}
+
 	var wg sync.WaitGroup
 	wg.Add(3)
 	go func() { defer wg.Done(); c.readLoop(ctx, cancel) }()
@@ -153,7 +185,10 @@ type wsClient struct {
 	broker *broker.Broker
 	log    *slog.Logger
 	user   string         // end-user identity from the trusted proxy header ("" if none)
-	policy *access.Policy // global access-level enforcement
+	ip     string         // client address, for audit attribution
+	policy  *access.Policy // global access-level enforcement
+	audit   audit.Recorder // signal-write audit recorder (never nil)
+	dialogs *DialogHub     // control-logic dialog fan-out (nil if disabled)
 
 	outCh    chan []byte        // serialised outgoing messages
 	updateCh chan broker.Update // raw updates from the broker
@@ -190,12 +225,14 @@ func (c *wsClient) dispatchLoop(ctx context.Context) {
 				continue
 			}
 			msg := outMsg{
-				Type:    "update",
+				Type:     "update",
-				DS:      u.Ref.DS,
+				DS:       u.Ref.DS,
-				Name:    u.Ref.Name,
+				Name:     u.Ref.Name,
-				TS:      u.Value.Timestamp.UTC().Format(time.RFC3339Nano),
+				TS:       u.Value.Timestamp.UTC().Format(time.RFC3339Nano),
-				Value:   u.Value.Data,
+				Value:    u.Value.Data,
-				Quality: u.Value.Quality.String(),
+				Quality:  u.Value.Quality.String(),
+				Severity: u.Value.Severity,
+				Status:   u.Value.Status,
 			}
 			b, err := json.Marshal(msg)
 			if err != nil {
@@ -248,6 +285,8 @@ func (c *wsClient) handleMessage(ctx context.Context, data []byte) {
 		c.handleWrite(ctx, msg)
 	case "history":
 		c.handleHistory(ctx, msg)
+	case "dialogResponse":
+		c.handleDialogResponse(ctx, msg)
 	default:
 		c.sendError(ctx, "UNKNOWN_TYPE", "unknown message type: "+msg.Type)
 	}
@@ -303,6 +342,14 @@ func (c *wsClient) handleWrite(ctx context.Context, msg inMsg) {
 		return
 	}
 
+	// Server variables are read-any but write only for control-logic editors, so a
+	// panel cannot mutate sequence state unless its user owns control-logic access.
+	if msg.DS == "srv" && c.policy != nil && !c.policy.CanEditLogic(c.policy.ResolveUser(c.user)) {
+		c.log.Warn("write: server variable denied", "name", msg.Name, "user", c.user)
+		c.sendError(ctx, "ACCESS_DENIED", "writing server variables requires control-logic access")
+		return
+	}
+
 	ds, ok := c.broker.Source(msg.DS)
 	if !ok {
 		c.log.Warn("write: unknown data source", "ds", msg.DS, "name", msg.Name)
@@ -336,10 +383,44 @@ func (c *wsClient) handleWrite(ctx context.Context, msg inMsg) {
 	// Attribute the write to the connecting end-user so data sources (EPICS) can
 	// act under that identity rather than the server's.
 	ctx = datasource.WithUser(ctx, c.user)
+	ev := audit.Event{
+		Actor:     c.user,
+		ActorType: audit.ActorUser,
+		Action:    "signal.write",
+		DS:        msg.DS,
+		Signal:    msg.Name,
+		Value:     formatAuditValue(value),
+		IP:        c.ip,
+		Outcome:   audit.OutcomeOK,
+	}
 	if err := ds.Write(ctx, msg.Name, value); err != nil {
 		c.log.Warn("write: ds.Write failed", "ds", msg.DS, "name", msg.Name, "err", err)
+		ev.Outcome = audit.OutcomeError
+		ev.Error = err.Error()
+		c.audit.Record(ev)
 		c.sendError(ctx, "WRITE_ERROR", err.Error())
+		return
 	}
+	c.audit.Record(ev)
+}
+
+// handleDialogResponse routes the answer to a control-logic input dialog. An
+// empty/null value means the user dismissed the dialog (drop it without
+// writing); otherwise the numeric value is written to the dialog's target.
+func (c *wsClient) handleDialogResponse(ctx context.Context, msg inMsg) {
+	if c.dialogs == nil || msg.ID == "" {
+		return
+	}
+	if len(msg.Value) == 0 || string(msg.Value) == "null" {
+		c.dialogs.cancel(msg.ID)
+		return
+	}
+	var num float64
+	if err := json.Unmarshal(msg.Value, &num); err != nil {
+		c.dialogs.cancel(msg.ID)
+		return
+	}
+	c.dialogs.respond(ctx, c, msg.ID, num)
 }
 
 func (c *wsClient) handleHistory(ctx context.Context, msg inMsg) {
@@ -416,6 +497,44 @@ func (c *wsClient) sendError(ctx context.Context, code, message string) {
 
 // ── Helpers ───────────────────────────────────────────────────────────────────
 
+// clientIP returns the best-effort client address for audit attribution,
+// preferring the X-Forwarded-For / X-Real-IP headers set by a reverse proxy and
+// falling back to the TCP peer address.
+func clientIP(r *http.Request) string {
+	if xff := r.Header.Get("X-Forwarded-For"); xff != "" {
+		if i := strings.IndexByte(xff, ','); i >= 0 {
+			return strings.TrimSpace(xff[:i])
+		}
+		return strings.TrimSpace(xff)
+	}
+	if xr := r.Header.Get("X-Real-IP"); xr != "" {
+		return strings.TrimSpace(xr)
+	}
+	if host, _, err := net.SplitHostPort(r.RemoteAddr); err == nil {
+		return host
+	}
+	return r.RemoteAddr
+}
+
+// formatAuditValue renders a written value as a compact string for the audit log.
+func formatAuditValue(v any) string {
+	switch x := v.(type) {
+	case string:
+		return x
+	case float64:
+		return strconv.FormatFloat(x, 'g', -1, 64)
+	case bool:
+		return strconv.FormatBool(x)
+	case nil:
+		return ""
+	default:
+		if b, err := json.Marshal(v); err == nil {
+			return string(b)
+		}
+		return ""
+	}
+}
+
 func metadataToPayload(m datasource.Metadata) *metaPayload {
 	return &metaPayload{
 		Type:        dataTypeName(m.Type),

internal/storage/store.go

@@ -474,16 +474,43 @@ func setXMLAttribute(data []byte, attr, value string) ([]byte, error) {
 	return []byte(s[:valStart] + value + s[valStart+valEnd:]), nil
 }
 
-// Delete removes the interface with the given ID.
+// Delete moves the interface with the given ID — and all of its version
+// backups — into a timestamped trash folder so it can be recovered if needed.
+// Nothing is destroyed; recovery is a matter of moving the files back.
 func (s *Store) Delete(id string) error {
 	if err := validateID(id); err != nil {
 		return ErrNotFound
 	}
-	err := os.Remove(s.filePath(id))
+	if _, err := os.Stat(s.filePath(id)); err != nil {
-	if errors.Is(err, os.ErrNotExist) {
+		if errors.Is(err, os.ErrNotExist) {
-		return ErrNotFound
+			return ErrNotFound
+		}
+		return err
 	}
-	return err
+
+	trashDir := filepath.Join(s.rootDir, "trash", "interfaces", fmt.Sprintf("%s.%d", id, time.Now().UnixMilli()))
+	if err := os.MkdirAll(trashDir, 0o755); err != nil {
+		return fmt.Errorf("create trash dir: %w", err)
+	}
+
+	// Move the current file plus every versioned backup (id.vN.xml), preserving
+	// their original names so a restore is a straight move-back.
+	entries, err := os.ReadDir(s.dir)
+	if err != nil {
+		return err
+	}
+	for _, e := range entries {
+		name := e.Name()
+		if e.IsDir() {
+			continue
+		}
+		if name == id+".xml" || (strings.HasPrefix(name, id+".v") && isVersioned(name)) {
+			if err := os.Rename(filepath.Join(s.dir, name), filepath.Join(trashDir, name)); err != nil {
+				return fmt.Errorf("move %s to trash: %w", name, err)
+			}
+		}
+	}
+	return nil
 }
 
 // Clone duplicates an interface, assigning a new unique ID.

web/src/App.tsx

@@ -4,6 +4,7 @@ import { wsClient } from './lib/ws';
 import ViewMode from './ViewMode';
 import EditMode from './EditMode';
 import FullscreenMode from './FullscreenMode';
+import ControlDialogs from './ControlDialogs';
 import { applyZoom, getStoredZoom } from './ZoomControl';
 import { AuthContext, DEFAULT_ME, fetchMe, canRead } from './lib/auth';
 import type { Interface, Me } from './lib/types';
@@ -69,6 +70,7 @@ export default function App() {
   return (
     <AuthContext.Provider value={me}>
       <div class="app-root">
+        <ControlDialogs />
         {wsStatus === 'disconnected' && (
           <div class="connection-banner">WebSocket disconnected — reconnecting…</div>
         )}

web/src/AuditViewer.tsx

@@ -0,0 +1,169 @@
+import { h } from 'preact';
+import { useState, useEffect, useCallback } from 'preact/hooks';
+
+// AuditEvent mirrors the JSON returned by GET /api/v1/audit (internal/audit.Event).
+interface AuditEvent {
+  time: string;
+  actor: string;
+  actorType: string; // "user" | "system"
+  action: string;
+  ds?: string;
+  signal?: string;
+  value?: string;
+  detail?: string;
+  ip?: string;
+  outcome: string; // "ok" | "error"
+  error?: string;
+}
+
+interface Props { onClose: () => void; }
+
+/** Convert an RFC3339/ISO timestamp to a compact local datetime string. */
+function fmtTime(iso: string): string {
+  const d = new Date(iso);
+  if (isNaN(d.getTime())) return iso;
+  const pad = (n: number) => String(n).padStart(2, '0');
+  return `${d.getFullYear()}-${pad(d.getMonth() + 1)}-${pad(d.getDate())} ${pad(d.getHours())}:${pad(d.getMinutes())}:${pad(d.getSeconds())}`;
+}
+
+/** Convert a datetime-local input value (local time) to an RFC3339 string. */
+function localToRFC3339(v: string): string {
+  if (!v) return '';
+  const d = new Date(v);
+  return isNaN(d.getTime()) ? '' : d.toISOString();
+}
+
+export default function AuditViewer({ onClose }: Props) {
+  const [events, setEvents] = useState<AuditEvent[]>([]);
+  const [loading, setLoading] = useState(false);
+  const [error, setError] = useState<string | null>(null);
+
+  // Filters
+  const [user, setUser] = useState('');
+  const [action, setAction] = useState('');
+  const [signal, setSignal] = useState('');
+  const [start, setStart] = useState('');
+  const [end, setEnd] = useState('');
+
+  const load = useCallback(async () => {
+    setLoading(true);
+    setError(null);
+    try {
+      const q = new URLSearchParams();
+      if (user.trim()) q.set('user', user.trim());
+      if (action) q.set('action', action);
+      if (signal.trim()) q.set('signal', signal.trim());
+      const s = localToRFC3339(start);
+      const e = localToRFC3339(end);
+      if (s) q.set('start', s);
+      if (e) q.set('end', e);
+      const res = await fetch(`/api/v1/audit?${q.toString()}`);
+      if (res.status === 403) throw new Error('You are not permitted to view the audit log.');
+      if (!res.ok) throw new Error(`HTTP ${res.status}`);
+      const data = await res.json();
+      setEvents(Array.isArray(data) ? data : []);
+    } catch (err) {
+      setError(err instanceof Error ? err.message : String(err));
+      setEvents([]);
+    } finally {
+      setLoading(false);
+    }
+  }, [user, action, signal, start, end]);
+
+  // Initial load.
+  useEffect(() => { load(); }, []); // eslint-disable-line react-hooks/exhaustive-deps
+
+  function resetFilters() {
+    setUser(''); setAction(''); setSignal(''); setStart(''); setEnd('');
+  }
+
+  return (
+    <div class="cl-overlay" onMouseDown={(e) => { if (e.target === e.currentTarget) onClose(); }}>
+      <div class="cl-modal audit-modal">
+        <header class="cl-header">
+          <span class="cl-title">Audit log</span>
+          <span class="hint cl-subtitle">Every system-affecting action (signal writes, control-logic and interface changes).</span>
+          <div class="cl-header-actions">
+            <button class="panel-btn" disabled={loading} onClick={load}>{loading ? 'Loading…' : 'Refresh'}</button>
+            <button class="panel-btn" onClick={onClose}>Close</button>
+          </div>
+        </header>
+
+        <div class="audit-filters">
+          <input class="audit-filter" type="text" placeholder="User" value={user}
+            onInput={(e) => setUser((e.target as HTMLInputElement).value)} />
+          <select class="audit-filter" value={action}
+            onChange={(e) => setAction((e.target as HTMLSelectElement).value)}>
+            <option value="">All actions</option>
+            <option value="signal.write">signal.write</option>
+            <option value="interface.create">interface.create</option>
+            <option value="interface.update">interface.update</option>
+            <option value="interface.delete">interface.delete</option>
+            <option value="controllogic.create">controllogic.create</option>
+            <option value="controllogic.update">controllogic.update</option>
+            <option value="controllogic.delete">controllogic.delete</option>
+          </select>
+          <input class="audit-filter" type="text" placeholder="Signal contains…" value={signal}
+            onInput={(e) => setSignal((e.target as HTMLInputElement).value)} />
+          <label class="audit-filter-label">From
+            <input class="audit-filter" type="datetime-local" value={start}
+              onInput={(e) => setStart((e.target as HTMLInputElement).value)} />
+          </label>
+          <label class="audit-filter-label">To
+            <input class="audit-filter" type="datetime-local" value={end}
+              onInput={(e) => setEnd((e.target as HTMLInputElement).value)} />
+          </label>
+          <button class="panel-btn" disabled={loading} onClick={load}>Apply</button>
+          <button class="panel-btn" onClick={resetFilters}>Reset</button>
+        </div>
+
+        {error && <div class="cl-error">{error}</div>}
+
+        <div class="audit-body">
+          {!error && events.length === 0 && !loading && (
+            <div class="hint audit-empty">No matching audit entries.</div>
+          )}
+          {events.length > 0 && (
+            <table class="audit-table">
+              <thead>
+                <tr>
+                  <th>Time</th>
+                  <th>Actor</th>
+                  <th>Action</th>
+                  <th>Source</th>
+                  <th>Signal / target</th>
+                  <th>Value</th>
+                  <th>Detail</th>
+                  <th>Client</th>
+                  <th>Result</th>
+                </tr>
+              </thead>
+              <tbody>
+                {events.map((ev, i) => (
+                  <tr key={i} class={ev.outcome === 'error' ? 'audit-row-error' : ''}>
+                    <td class="audit-time">{fmtTime(ev.time)}</td>
+                    <td>
+                      <span class={`audit-actor-tag audit-actor-${ev.actorType}`}>{ev.actorType}</span>
+                      {' '}{ev.actor || '—'}
+                    </td>
+                    <td>{ev.action}</td>
+                    <td>{ev.ds || '—'}</td>
+                    <td class="audit-signal" title={ev.signal}>{ev.signal || '—'}</td>
+                    <td class="audit-value" title={ev.value}>{ev.value ?? '—'}</td>
+                    <td class="audit-detail" title={ev.detail}>{ev.detail || '—'}</td>
+                    <td>{ev.ip || '—'}</td>
+                    <td>
+                      {ev.outcome === 'error'
+                        ? <span class="audit-result-err" title={ev.error}>error</span>
+                        : <span class="audit-result-ok">ok</span>}
+                    </td>
+                  </tr>
+                ))}
+              </tbody>
+            </table>
+          )}
+        </div>
+      </div>
+    </div>
+  );
+}

web/src/ContextualHelp.tsx

@@ -1,95 +0,0 @@
-import { h } from 'preact';
-import { useState, useRef, useEffect } from 'preact/hooks';
-
-interface Props {
-  mode: 'view' | 'edit';
-  onOpenManual: (section?: string) => void;
-}
-
-const TIPS: Record<string, Array<{ text: string; section?: string }>> = {
-  view: [
-    { text: 'Click any interface in the left panel to load it on the canvas.', section: 'view' },
-    { text: 'Right-click a widget to view signal info or export data as CSV.', section: 'view' },
-    { text: 'The ● Live button shows live streaming is active. Use the date pickers to load historical data.', section: 'history' },
-    { text: 'Click Edit (top-right) to open the drag-and-drop panel builder.', section: 'edit' },
-    { text: 'Use the Share button on a panel to grant access to users or groups.', section: 'sharing' },
-    { text: 'The ⚙ Control logic button opens server-side automation that runs even with no panel open.', section: 'control' },
-    { text: 'The dot in the status chip turns green when the WebSocket is connected.', section: 'view' },
-  ],
-  edit: [
-    { text: 'Drag a signal from the left tree onto the canvas to create a widget.', section: 'edit' },
-    { text: 'Click a widget to select it, then adjust its properties on the right.', section: 'edit' },
-    { text: 'Ctrl+click to select multiple widgets; then use the align toolbar.', section: 'edit' },
-    { text: 'Ctrl+Z to undo, Ctrl+Y to redo. Up to 50 steps are remembered.', section: 'shortcuts' },
-    { text: 'Use "+ Synthetic" in the signal tree to create computed/filtered signals.', section: 'signals' },
-    { text: 'Switch to the Logic tab to add interactive behaviour with a node-graph flow editor.', section: 'logic' },
-    { text: 'Add Local variables for set-points and counters that live inside the panel.', section: 'edit' },
-    { text: 'Arrow keys nudge the selected widget by 1 px (Shift for grid size).', section: 'shortcuts' },
-  ],
-};
-
-export default function ContextualHelp({ mode, onOpenManual }: Props) {
-  const [open, setOpen] = useState(false);
-  const [tipIndex, setTipIndex] = useState(0);
-  const ref = useRef<HTMLDivElement>(null);
-  const tips = TIPS[mode];
-
-  // Close on outside click
-  useEffect(() => {
-    if (!open) return;
-    function handler(e: MouseEvent) {
-      if (ref.current && !ref.current.contains(e.target as Node)) {
-        setOpen(false);
-      }
-    }
-    document.addEventListener('mousedown', handler);
-    return () => document.removeEventListener('mousedown', handler);
-  }, [open]);
-
-  // Cycle to a new random tip each time the popover opens
-  function handleOpen() {
-    setTipIndex(t => (t + 1) % tips.length);
-    setOpen(o => !o);
-  }
-
-  const tip = tips[tipIndex];
-
-  return (
-    <div class="ctx-help" ref={ref}>
-      <button
-        class="ctx-help-btn"
-        onClick={handleOpen}
-        title="Contextual help"
-        aria-label="Open contextual help"
-        aria-expanded={open}
-      >
-        ?
-      </button>
-
-      {open && (
-        <div class="ctx-help-popover" role="tooltip">
-          <div class="ctx-help-tip">
-            <span class="ctx-help-icon">💡</span>
-            <span>{tip.text}</span>
-          </div>
-
-          <div class="ctx-help-footer">
-            <button
-              class="ctx-help-nav"
-              onClick={() => setTipIndex(t => (t + 1) % tips.length)}
-              title="Next tip"
-            >
-              Next tip →
-            </button>
-            <button
-              class="ctx-help-link"
-              onClick={() => { setOpen(false); onOpenManual(tip.section); }}
-            >
-              Open manual ↗
-            </button>
-          </div>
-        </div>
-      )}
-    </div>
-  );
-}

web/src/ControlDialogs.tsx

@@ -0,0 +1,60 @@
+import { h, Fragment } from 'preact';
+import { useState, useEffect } from 'preact/hooks';
+import { wsClient } from './lib/ws';
+import { controlDialogs, dismissControlDialog, type ControlDialog } from './lib/controldialogs';
+
+// Renders dialogs pushed by server-side control-logic action.dialog nodes over
+// the WebSocket. Mounted once globally (App) since these are addressed to the
+// connected user, independent of which panel is open. info/error dialogs are
+// acknowledgements; input dialogs send a numeric response back to the server.
+export default function ControlDialogs() {
+  const [reqs, setReqs] = useState<ControlDialog[]>([]);
+  useEffect(() => controlDialogs.subscribe(setReqs), []);
+  if (reqs.length === 0) return null;
+  return <Fragment>{reqs.map(r => <ControlDialogModal key={r.id} req={r} />)}</Fragment>;
+}
+
+function ControlDialogModal({ req }: { req: ControlDialog; key?: string }) {
+  const isInput = req.kind === 'input';
+  const [val, setVal] = useState('');
+
+  function ok() {
+    if (isInput) {
+      const n = parseFloat(val);
+      wsClient.sendDialogResponse(req.id, Number.isFinite(n) ? n : null);
+    }
+    dismissControlDialog(req.id);
+  }
+  function cancel() {
+    if (isInput) wsClient.sendDialogResponse(req.id, null);
+    dismissControlDialog(req.id);
+  }
+
+  function onKey(e: KeyboardEvent) {
+    if (e.key === 'Enter') { e.preventDefault(); ok(); }
+    if (e.key === 'Escape') { e.preventDefault(); cancel(); }
+  }
+
+  return (
+    <div class="logic-dialog-backdrop" onKeyDown={onKey}>
+      <div class={`logic-dialog logic-dialog-${req.kind}`} role="dialog">
+        <div class="logic-dialog-header">
+          {req.title || (req.kind === 'error' ? 'Error' : isInput ? 'Input required' : 'Info')}
+        </div>
+        {req.message && <div class="logic-dialog-message">{req.message}</div>}
+        {isInput && (
+          <div class="logic-dialog-field">
+            <input class="prop-input logic-dialog-input" type="number"
+              autoFocus value={val}
+              onInput={(e) => setVal((e.target as HTMLInputElement).value)}
+              onKeyDown={onKey} />
+          </div>
+        )}
+        <div class="logic-dialog-actions">
+          {isInput && <button class="panel-btn" onClick={cancel}>Cancel</button>}
+          <button class="panel-btn panel-btn-primary" onClick={ok}>OK</button>
+        </div>
+      </div>
+    </div>
+  );
+}

web/src/ControlLogicEditor.tsx

@@ -1,6 +1,6 @@
 import { h, Fragment } from 'preact';
 import { useState, useEffect, useRef } from 'preact/hooks';
-import SearchableSelect from './SearchableSelect';
+import SignalPicker, { SignalOption } from './SignalPicker';
 import LuaEditor from './LuaEditor';
 import { checkExpr } from './lib/expr';
 
@@ -18,7 +18,8 @@ type CLNodeKind =
   | 'action.write'
   | 'action.delay'
   | 'action.log'
-  | 'action.lua';
+  | 'action.lua'
+  | 'action.dialog';
 
 interface CLNode {
   id: string;
@@ -55,6 +56,11 @@ const NODE_W = 11.5 * REM;
 const PORT_TOP = 2 * REM;
 const PORT_GAP = 1.375 * REM;
 const PORT_R = 0.375 * REM;
+// Ports sit inside the node's padding box, offset from the node border-box origin
+// by the node borders (3px colored top accent, 1px sides). Anchors add the same
+// offsets so wires meet the port centers, not their top edges.
+const BORDER = 1;
+const BORDER_TOP = 3;
 
 interface PaletteEntry { kind: CLNodeKind; label: string; params: Record<string, string>; }
 
@@ -71,6 +77,7 @@ const PALETTE: PaletteEntry[] = [
   { kind: 'action.delay',      label: 'Delay',     params: { ms: '500' } },
   { kind: 'action.log',        label: 'Log',       params: { expr: '', label: '' } },
   { kind: 'action.lua',        label: 'Lua script', params: { script: '-- get("ds:name") reads, set("ds:name", v) writes,\n-- log("msg") logs to the server.\n' } },
+  { kind: 'action.dialog',     label: 'Dialog',    params: { kind: 'info', title: '', message: '', users: '', groups: '', target: '' } },
 ];
 
 const KIND_LABEL: Record<CLNodeKind, string> = {
@@ -86,6 +93,7 @@ const KIND_LABEL: Record<CLNodeKind, string> = {
   'action.delay': 'Delay',
   'action.log': 'Log',
   'action.lua': 'Lua script',
+  'action.dialog': 'Dialog',
 };
 
 const THRESHOLD_OPS = ['>', '<', '>=', '<=', '==', '!='] as const;
@@ -117,11 +125,11 @@ function nodeHeight(kind: CLNodeKind): number { return PORT_TOP + outputs(kind).
 
 function genId(): string { return 'n_' + Math.random().toString(36).slice(2, 9); }
 
-function inAnchor(n: CLNode) { return { x: n.x, y: n.y + PORT_TOP }; }
+function inAnchor(n: CLNode) { return { x: n.x + BORDER, y: n.y + BORDER_TOP + PORT_TOP }; }
 function outAnchor(n: CLNode, port: string) {
   const ports = outputs(n.kind);
   const i = Math.max(0, ports.findIndex(p => p.id === port));
-  return { x: n.x + NODE_W, y: n.y + PORT_TOP + i * PORT_GAP };
+  return { x: n.x + NODE_W - BORDER, y: n.y + BORDER_TOP + PORT_TOP + i * PORT_GAP };
 }
 function wirePathStr(x1: number, y1: number, x2: number, y2: number): string {
   const dx = Math.max(40, Math.abs(x2 - x1) / 2);
@@ -139,6 +147,16 @@ export default function ControlLogicEditor({ onClose }: Props) {
   const [dirty, setDirty] = useState(false);
   const [busy, setBusy] = useState(false);
   const [error, setError] = useState<string | null>(null);
+  const [showCloseConfirm, setShowCloseConfirm] = useState(false);
+
+  // Closing with unsaved changes prompts instead of silently discarding them.
+  function requestClose() {
+    if (dirty) { setShowCloseConfirm(true); return; }
+    onClose();
+  }
+  async function saveAndClose() {
+    if (await saveGraph()) { setShowCloseConfirm(false); onClose(); }
+  }
 
   async function reload() {
     try {
@@ -180,8 +198,8 @@ export default function ControlLogicEditor({ onClose }: Props) {
     }
   }
 
-  async function saveGraph() {
+  async function saveGraph(): Promise<boolean> {
-    if (!graph) return;
+    if (!graph) return false;
     setBusy(true);
     setError(null);
     try {
@@ -191,8 +209,10 @@ export default function ControlLogicEditor({ onClose }: Props) {
       if (!res.ok) throw new Error(`HTTP ${res.status}`);
       setDirty(false);
       await reload();
+      return true;
     } catch (err) {
       setError(`Save failed: ${err instanceof Error ? err.message : err}`);
+      return false;
     } finally {
       setBusy(false);
     }
@@ -240,7 +260,7 @@ export default function ControlLogicEditor({ onClose }: Props) {
   }
 
   return (
-    <div class="cl-overlay" onMouseDown={(e) => { if (e.target === e.currentTarget) onClose(); }}>
+    <div class="cl-overlay" onMouseDown={(e) => { if (e.target === e.currentTarget) requestClose(); }}>
       <div class="cl-modal">
         <header class="cl-header">
           <span class="cl-title">Control logic</span>
@@ -248,7 +268,7 @@ export default function ControlLogicEditor({ onClose }: Props) {
           <div class="cl-header-actions">
             {graph && dirty && <span class="cl-dirty">unsaved</span>}
             {graph && <button class="panel-btn" disabled={busy || !dirty} onClick={saveGraph}>Save</button>}
-            <button class="panel-btn" onClick={onClose}>Close</button>
+            <button class="panel-btn" onClick={requestClose}>Close</button>
           </div>
         </header>
 
@@ -299,6 +319,21 @@ export default function ControlLogicEditor({ onClose }: Props) {
             )}
           </div>
         </div>
+
+        {showCloseConfirm && (
+          <div class="cl-confirm-overlay" onMouseDown={(e) => { if (e.target === e.currentTarget) setShowCloseConfirm(false); }}>
+            <div class="cl-confirm">
+              <div class="cl-confirm-title">Unsaved changes</div>
+              <p class="hint">This graph has unsaved changes. What would you like to do?</p>
+              <div class="cl-confirm-actions">
+                <button class="panel-btn" onClick={() => setShowCloseConfirm(false)}>Cancel</button>
+                <button class="panel-btn" disabled={busy}
+                  onClick={() => { setShowCloseConfirm(false); onClose(); }}>Close without saving</button>
+                <button class="panel-btn panel-btn-primary" disabled={busy} onClick={saveAndClose}>Save and close</button>
+              </div>
+            </div>
+          </div>
+        )}
       </div>
     </div>
   );
@@ -341,12 +376,15 @@ function FlowEditor({ graph, onChange }: {
     } catch {}
   }
 
-  // Bare-name write targets are graph-local variables; offer them under 'local'.
+  // Graph-local write targets (bare name, or an explicit "local:" prefix) become
+  // the suggestions offered when the target data source is 'local'.
   const localNames = Array.from(new Set(
     nodes.filter(n => n.kind === 'action.write')
       .map(n => n.params.target ?? '')
+      .map(t => t.startsWith('local:') ? t.slice('local:'.length) : t)
       .filter(t => t && !t.includes(':'))
   ));
+  // 'srv' is a registered data source, so it already appears in dataSources.
   const dsOptions = ['local', 'sys', ...dataSources];
   function signalOptions(ds: string): string[] {
     if (ds === 'local') return localNames;
@@ -354,6 +392,15 @@ function FlowEditor({ graph, onChange }: {
     return dsSignals[ds] ?? [];
   }
 
+  // Flatten every known ds:name into a single list for the fuzzy SignalPicker,
+  // and a hook to lazily load all data sources' signals when a picker opens.
+  function allSignalOptions(): SignalOption[] {
+    const out: SignalOption[] = [];
+    for (const ds of dsOptions) for (const name of signalOptions(ds)) out.push({ ds, name });
+    return out;
+  }
+  function openAllSignals() { dsOptions.forEach(ds => loadSignals(ds)); }
+
   const selected = nodes.find(n => n.id === selectedNode) ?? null;
 
   useEffect(() => {
@@ -573,19 +620,13 @@ function FlowEditor({ graph, onChange }: {
             <div class="wizard-section-title">{KIND_LABEL[selected.kind]}</div>
 
             {(selected.kind === 'trigger.threshold' || selected.kind === 'trigger.change' || selected.kind === 'trigger.alarm') && (() => {
-              const { ds, name } = splitRef(selected.params.signal ?? '');
               return (
                 <Fragment>
-                  <div class="wizard-field">
-                    <label>Data source</label>
-                    <SearchableSelect value={ds} options={dataSources}
-                      onSelect={(newDs) => { loadSignals(newDs); patchParams(selected.id, { signal: `${newDs}:` }); }} />
-                  </div>
                   <div class="wizard-field">
                     <label>Signal</label>
-                    <SearchableSelect value={name} options={signalOptions(ds)}
+                    <SignalPicker value={selected.params.signal ?? ''} options={allSignalOptions()}
-                      onSelect={(sig) => patchParams(selected.id, { signal: `${ds}:${sig}` })}
+                      onOpen={openAllSignals}
-                      placeholder={ds ? 'Search signals…' : 'Select data source first'} />
+                      onChange={(ref) => patchParams(selected.id, { signal: ref })} />
                   </div>
                   {selected.kind === 'trigger.threshold' && (
                     <div class="wizard-field wizard-field-row">
@@ -661,7 +702,7 @@ function FlowEditor({ graph, onChange }: {
               <ExprField label="Condition" value={selected.params.cond ?? ''}
                 onChange={(v) => patchParams(selected.id, { cond: v })}
                 onInsert={(ds, sig) => insertRef(selected.id, 'cond', ds, sig)}
-                dsOptions={dsOptions} signalOptions={signalOptions} loadSignals={loadSignals}
+                allSignals={allSignalOptions()} onOpenSignals={openAllSignals}
                 hint="True → 'then' port, false → 'else'. e.g. {stub:level} > 5 && temp < 100. {sys:time}=epoch seconds, {sys:dt}=seconds since the trigger last fired." />
             )}
 
@@ -685,36 +726,30 @@ function FlowEditor({ graph, onChange }: {
                   <ExprField label="While condition" value={selected.params.cond ?? ''}
                     onChange={(v) => patchParams(selected.id, { cond: v })}
                     onInsert={(ds, sig) => insertRef(selected.id, 'cond', ds, sig)}
-                    dsOptions={dsOptions} signalOptions={signalOptions} loadSignals={loadSignals}
+                    allSignals={allSignalOptions()} onOpenSignals={openAllSignals}
                     hint="Loops the 'body' port while true (capped). e.g. {stub:level} < 90" />
                 )}
                 <p class="hint">Runs the <b>body</b> port repeatedly, then continues on <b>done</b>.</p>
               </Fragment>
             )}
 
-            {selected.kind === 'action.write' && (() => {
+            {selected.kind === 'action.write' && (
-              const { ds, name } = splitRef(selected.params.target ?? '');
+              <Fragment>
-              return (
+                <div class="wizard-field">
-                <Fragment>
+                  <label>Target signal / variable</label>
-                  <div class="wizard-field">
+                  <SignalPicker value={selected.params.target ?? ''} options={allSignalOptions()}
-                    <label>Target data source</label>
+                    onOpen={openAllSignals} allowFreeform
-                    <SearchableSelect value={ds} options={dsOptions}
+                    onChange={(ref) => patchParams(selected.id, { target: ref })} />
-                      onSelect={(newDs) => { loadSignals(newDs); patchParams(selected.id, { target: `${newDs}:` }); }} />
+                  <p class="hint">Pick a signal, or type <code>local:name</code> for a graph-local var
-                  </div>
+                    or <code>srv:name</code> for a server variable that panels can read.</p>
-                  <div class="wizard-field">
+                </div>
-                    <label>Target signal</label>
+                <ExprField label="Value (expression)" value={selected.params.expr ?? ''}
-                    <SearchableSelect value={name} options={signalOptions(ds)}
+                  onChange={(v) => patchParams(selected.id, { expr: v })}
-                      onSelect={(sig) => patchParams(selected.id, { target: `${ds}:${sig}` })}
+                  onInsert={(ds2, sig) => insertRef(selected.id, 'expr', ds2, sig)}
-                      placeholder={ds ? 'Search signals…' : 'Select data source first'} />
+                  allSignals={allSignalOptions()} onOpenSignals={openAllSignals}
-                  </div>
+                  hint="Write to a data source signal, a bare local var, or srv:name for a server variable panels can read. e.g. ({stub:a} - {stub:b}) / {sys:dt}." />
-                  <ExprField label="Value (expression)" value={selected.params.expr ?? ''}
+              </Fragment>
-                    onChange={(v) => patchParams(selected.id, { expr: v })}
+            )}
-                    onInsert={(ds2, sig) => insertRef(selected.id, 'expr', ds2, sig)}
-                    dsOptions={dsOptions} signalOptions={signalOptions} loadSignals={loadSignals}
-                    hint="Write to a data source signal, or a bare name to store a graph-local var. e.g. ({stub:a} - {stub:b}) / {sys:dt}." />
-                </Fragment>
-              );
-            })()}
 
             {selected.kind === 'action.delay' && (
               <div class="wizard-field">
@@ -735,7 +770,7 @@ function FlowEditor({ graph, onChange }: {
                 <ExprField label="Value (expression)" value={selected.params.expr ?? ''}
                   onChange={(v) => patchParams(selected.id, { expr: v })}
                   onInsert={(ds2, sig) => insertRef(selected.id, 'expr', ds2, sig)}
-                  dsOptions={dsOptions} signalOptions={signalOptions} loadSignals={loadSignals}
+                  allSignals={allSignalOptions()} onOpenSignals={openAllSignals}
                   hint="Logs this value to the server log — handy for debugging a flow." />
               </Fragment>
             )}
@@ -753,6 +788,54 @@ function FlowEditor({ graph, onChange }: {
               </div>
             )}
 
+            {selected.kind === 'action.dialog' && (
+              <Fragment>
+                <div class="wizard-field">
+                  <label>Type</label>
+                  <select class="prop-input" value={selected.params.kind ?? 'info'}
+                    onChange={(e) => patchParams(selected.id, { kind: (e.target as HTMLSelectElement).value })}>
+                    <option value="info">Info</option>
+                    <option value="error">Error</option>
+                    <option value="input">Input (ask for a value)</option>
+                  </select>
+                </div>
+                <div class="wizard-field">
+                  <label>Title</label>
+                  <input class="prop-input" value={selected.params.title ?? ''}
+                    placeholder="dialog title"
+                    onInput={(e) => patchParams(selected.id, { title: (e.target as HTMLInputElement).value })} />
+                </div>
+                <div class="wizard-field">
+                  <label>Message</label>
+                  <textarea class="prop-input" rows={3} value={selected.params.message ?? ''}
+                    placeholder="shown to the user"
+                    onInput={(e) => patchParams(selected.id, { message: (e.target as HTMLTextAreaElement).value })} />
+                </div>
+                {selected.params.kind === 'input' && (
+                  <div class="wizard-field">
+                    <label>Response variable</label>
+                    <input class="prop-input" value={selected.params.target ?? ''}
+                      placeholder="srv:approved"
+                      onInput={(e) => patchParams(selected.id, { target: (e.target as HTMLInputElement).value })} />
+                    <p class="hint">The user's number is written here (e.g. <code>srv:approved</code>); read it on a later activation.</p>
+                  </div>
+                )}
+                <div class="wizard-field">
+                  <label>Users (optional)</label>
+                  <input class="prop-input" value={selected.params.users ?? ''}
+                    placeholder="alice, bob"
+                    onInput={(e) => patchParams(selected.id, { users: (e.target as HTMLInputElement).value })} />
+                </div>
+                <div class="wizard-field">
+                  <label>Groups (optional)</label>
+                  <input class="prop-input" value={selected.params.groups ?? ''}
+                    placeholder="operators"
+                    onInput={(e) => patchParams(selected.id, { groups: (e.target as HTMLInputElement).value })} />
+                  <p class="hint">Comma-separated. Leave both empty to show the dialog to every connected user.</p>
+                </div>
+              </Fragment>
+            )}
+
             <button class="panel-btn" style="margin-top:1rem;" onClick={() => deleteNode(selected.id)}>Delete node</button>
           </Fragment>
         )}
@@ -774,17 +857,15 @@ function FlowEditor({ graph, onChange }: {
   }
 }
 
-function ExprField({ label, value, onChange, onInsert, dsOptions, signalOptions, loadSignals, hint }: {
+function ExprField({ label, value, onChange, onInsert, allSignals, onOpenSignals, hint }: {
   label: string;
   value: string;
   onChange: (v: string) => void;
   onInsert: (ds: string, sig: string) => void;
-  dsOptions: string[];
+  allSignals: SignalOption[];
-  signalOptions: (ds: string) => string[];
+  onOpenSignals: () => void;
-  loadSignals: (ds: string) => void;
   hint: string;
 }) {
-  const [insDs, setInsDs] = useState('');
   const err = checkExpr(value);
   return (
     <div class="wizard-field">
@@ -794,11 +875,9 @@ function ExprField({ label, value, onChange, onInsert, dsOptions, signalOptions,
         onInput={(e) => onChange((e.target as HTMLInputElement).value)} />
       {err && <p class="wizard-error">{err}</p>}
       <div class="flow-expr-insert">
-        <SearchableSelect value={insDs} options={dsOptions}
+        <SignalPicker value="" options={allSignals} onOpen={onOpenSignals}
-          onSelect={(ds) => { setInsDs(ds); loadSignals(ds); }} placeholder="ds…" />
+          placeholder="+ insert signal"
-        <SearchableSelect value="" options={signalOptions(insDs)}
+          onChange={(ref) => { const s = splitRef(ref); onInsert(s.ds, s.name); }} />
-          onSelect={(sig) => onInsert(insDs, sig)}
-          placeholder={insDs ? '+ insert signal' : 'pick ds first'} />
       </div>
       <p class="hint">{hint}</p>
     </div>
@@ -821,6 +900,7 @@ function nodeSummary(n: CLNode): string {
     case 'action.delay':      return `wait ${n.params.ms || '0'} ms`;
     case 'action.log':        return `log ${n.params.label ? n.params.label + ': ' : ''}${n.params.expr || ''}`;
     case 'action.lua':        return 'Lua script';
+    case 'action.dialog':     return `${n.params.kind || 'info'} dialog${n.params.title ? ': ' + n.params.title : ''}`;
     default:                  return '';
   }
 }

web/src/EditMode.tsx

@@ -8,7 +8,6 @@ import EditCanvas, { genWidgetId, DEFAULT_SIZES } from './EditCanvas';
 import PlotPanelCanvas from './PlotPanelCanvas';
 import LogicEditor from './LogicEditor';
 import PropertiesPane from './PropertiesPane';
-import ContextualHelp from './ContextualHelp';
 import HelpModal from './HelpModal';
 import ZoomControl from './ZoomControl';
 import { useAuth, canWrite } from './lib/auth';
@@ -626,7 +625,6 @@ export default function EditMode({ initial, onDone }: Props) {
 
         <div class="toolbar-right">
           <ZoomControl />
-          <ContextualHelp mode="edit" onOpenManual={openHelp} />
           <button class="icon-btn help-manual-btn" onClick={() => openHelp('edit')} title="Open user manual">📖</button>
           <button class="toolbar-btn" onClick={handleImport}>Import</button>
           <button class="toolbar-btn" onClick={handleExport}>Export</button>

web/src/HelpModal.tsx

@@ -403,6 +403,7 @@ function DiagramSignalTree() {
 
 const SECTIONS = [
   { id: 'start',     label: 'Getting Started' },
+  { id: 'tips',      label: 'Quick Tips' },
   { id: 'view',      label: 'View Mode' },
   { id: 'edit',      label: 'Edit Mode' },
   { id: 'widgets',   label: 'Widgets' },
@@ -411,10 +412,68 @@ const SECTIONS = [
   { id: 'logic',     label: 'Panel Logic' },
   { id: 'control',   label: 'Control Logic' },
   { id: 'sharing',   label: 'Sharing & Access' },
+  { id: 'audit',     label: 'Audit Log' },
   { id: 'history',   label: 'Historical Data' },
   { id: 'shortcuts', label: 'Keyboard Shortcuts' },
 ];
 
+// Quick tips, grouped by the mode they apply to. Each links to the manual
+// section that covers it in depth. (Previously surfaced via a floating
+// contextual-help popover; now consolidated here in the manual.)
+const TIPS: Record<'view' | 'edit', Array<{ text: string; section: string }>> = {
+  view: [
+    { text: 'Click any interface in the left panel to load it on the canvas.', section: 'view' },
+    { text: 'Right-click a widget to view signal info or export data as CSV.', section: 'view' },
+    { text: 'The ● Live button shows live streaming is active. Use the date pickers to load historical data.', section: 'history' },
+    { text: 'Click Edit (top-right) to open the drag-and-drop panel builder.', section: 'edit' },
+    { text: 'Use the Share button on a panel to grant access to users or groups.', section: 'sharing' },
+    { text: 'The ⚙ Control logic button opens server-side automation that runs even with no panel open.', section: 'control' },
+    { text: 'The 🛡 Audit button (for permitted users) opens the log of system-affecting actions.', section: 'audit' },
+    { text: 'The status chip turns green and shows your username when the WebSocket is connected.', section: 'view' },
+  ],
+  edit: [
+    { text: 'Drag a signal from the left tree onto the canvas to create a widget.', section: 'edit' },
+    { text: 'Click a widget to select it, then adjust its properties on the right.', section: 'edit' },
+    { text: 'Ctrl+click to select multiple widgets; then use the align toolbar.', section: 'edit' },
+    { text: 'Ctrl+Z to undo, Ctrl+Y to redo. Up to 50 steps are remembered.', section: 'shortcuts' },
+    { text: 'Use "+ Synthetic" in the signal tree to create computed/filtered signals.', section: 'signals' },
+    { text: 'Switch to the Logic tab to add interactive behaviour with a node-graph flow editor.', section: 'logic' },
+    { text: 'Add Local variables for set-points and counters that live inside the panel.', section: 'edit' },
+    { text: 'Arrow keys nudge the selected widget by 1 px (Shift for grid size).', section: 'shortcuts' },
+  ],
+};
+
+function SectionTips({ onNavigate }: { onNavigate: (section: string) => void }) {
+  const groups: Array<['view' | 'edit', string]> = [
+    ['view', 'In View mode'],
+    ['edit', 'In Edit mode'],
+  ];
+  return (
+    <div>
+      <p class="help-lead">
+        A handful of quick pointers to get the most out of uopi. Click any tip to jump to the
+        section that explains it in detail.
+      </p>
+      {groups.map(([mode, title]) => (
+        <div key={mode}>
+          <h3 class="help-h3">{title}</h3>
+          <ul class="help-tips-list">
+            {TIPS[mode].map(tip => (
+              <li key={tip.text}>
+                <button class="help-tip-item" onClick={() => onNavigate(tip.section)}>
+                  <span class="help-tip-icon">💡</span>
+                  <span class="help-tip-text">{tip.text}</span>
+                  <span class="help-tip-go">↗</span>
+                </button>
+              </li>
+            ))}
+          </ul>
+        </div>
+      ))}
+    </div>
+  );
+}
+
 function SectionStart() {
   return (
     <div>
@@ -481,8 +540,10 @@ function SectionView() {
 
       <h3 class="help-h3">Connection status</h3>
       <p>
-        The coloured chip in the top-right shows the WebSocket connection state.
+        The coloured chip in the top-right shows the WebSocket connection state. When connected it
-        A red <em>"disconnected"</em> banner appears at the top while reconnecting — live values will resume automatically.
+        reads <em>"connected as &lt;your username&gt;"</em>, so you can confirm the identity your
+        actions are attributed to in the audit log. A red <em>"disconnected"</em> banner appears at
+        the top while reconnecting — live values will resume automatically.
       </p>
     </div>
   );
@@ -677,6 +738,44 @@ function SectionSharing() {
   );
 }
 
+function SectionAudit() {
+  return (
+    <div>
+      <p class="help-lead">
+        When the server is configured with <code>[audit] enabled = true</code>, every
+        <strong> system-affecting action</strong> is appended to an append-only log so it can be
+        reviewed later. Permitted users open it with the <strong>🛡 Audit</strong> button in the
+        view-mode toolbar.
+      </p>
+
+      <h3 class="help-h3">What gets recorded</h3>
+      <ul class="help-list">
+        <li><strong>Signal writes</strong> — both user-initiated (set-value widgets, buttons, panel
+          logic) and automated writes from the control-logic engine.</li>
+        <li><strong>Interface changes</strong> — panels created, updated, or deleted.</li>
+        <li><strong>Control-logic changes</strong> — graphs created, updated, or deleted.</li>
+      </ul>
+      <p>Each entry records the time, the actor (username, or the graph name for automated
+        actions), the action, the affected data source / signal and value, the client address, and
+        whether it succeeded.</p>
+
+      <h3 class="help-h3">Viewing the log</h3>
+      <ul class="help-list">
+        <li>The viewer lists the most recent events first.</li>
+        <li>Filter by user, action, signal, or a start/end time range.</li>
+        <li>System (automated) actions are tagged distinctly from user actions.</li>
+      </ul>
+
+      <p class="help-callout">
+        Access to the audit log is gated by an allowlist (<code>audit.readers</code> in the config),
+        following the same model as logic editing: an empty list means every user may view it,
+        otherwise only the listed users or groups can. The 🛡 Audit button is hidden for users who
+        are not permitted.
+      </p>
+    </div>
+  );
+}
+
 function SectionWidgets() {
   return (
     <div>
@@ -858,8 +957,9 @@ function SectionShortcuts() {
   );
 }
 
-const SECTION_COMPONENTS: Record<string, () => JSX.Element> = {
+const SECTION_COMPONENTS: Record<string, (props: { onNavigate: (section: string) => void }) => JSX.Element> = {
   start:     SectionStart,
+  tips:      SectionTips,
   view:      SectionView,
   edit:      SectionEdit,
   widgets:   SectionWidgets,
@@ -868,6 +968,7 @@ const SECTION_COMPONENTS: Record<string, () => JSX.Element> = {
   logic:     SectionLogic,
   control:   SectionControl,
   sharing:   SectionSharing,
+  audit:     SectionAudit,
   history:   SectionHistory,
   shortcuts: SectionShortcuts,
 };
@@ -877,7 +978,8 @@ const SECTION_COMPONENTS: Record<string, () => JSX.Element> = {
 export default function HelpModal({ initialSection = 'start', onClose }: Props) {
   const [active, setActive] = useState(initialSection);
 
-  const Content = SECTION_COMPONENTS[active] ?? SectionStart;
+  const Content: (props: { onNavigate: (section: string) => void }) => JSX.Element =
+    SECTION_COMPONENTS[active] ?? SectionStart;
 
   // Close on backdrop click
   function handleBackdrop(e: MouseEvent) {
@@ -915,7 +1017,7 @@ export default function HelpModal({ initialSection = 'start', onClose }: Props)
           {/* Content area */}
           <div class="help-content">
             <h2 class="help-h2">{SECTIONS.find(s => s.id === active)?.label}</h2>
-            <Content />
+            <Content onNavigate={setActive} />
           </div>
         </div>
       </div>

web/src/LogicEditor.tsx

@@ -1,6 +1,6 @@
 import { h, Fragment } from 'preact';
 import { useState, useEffect, useRef } from 'preact/hooks';
-import SearchableSelect from './SearchableSelect';
+import SignalPicker, { SignalOption } from './SignalPicker';
 import { checkExpr } from './lib/expr';
 import type { LogicGraph, LogicNode, LogicNodeKind, LogicWire, StateVar, Widget } from './lib/types';
 
@@ -37,6 +37,11 @@ const NODE_W = 11.5 * REM;  // node width
 const PORT_TOP = 2 * REM;   // y of the first port row, relative to node top
 const PORT_GAP = 1.375 * REM; // vertical spacing between stacked output ports
 const PORT_R = 0.375 * REM; // port radius (half the 0.75rem dot)
+// Ports sit inside the node's padding box, offset from the node border-box origin
+// by the node borders (3px colored top accent, 1px sides). Anchors add the same
+// offsets so wires meet the port centers, not their top edges.
+const BORDER = 1;
+const BORDER_TOP = 3;
 
 interface PaletteEntry {
   kind: LogicNodeKind;
@@ -114,11 +119,11 @@ function nodeHeight(kind: LogicNodeKind): number {
 function genId(): string { return 'n_' + Math.random().toString(36).slice(2, 9); }
 
 // Port anchors in canvas coordinates.
-function inAnchor(n: LogicNode) { return { x: n.x, y: n.y + PORT_TOP }; }
+function inAnchor(n: LogicNode) { return { x: n.x + BORDER, y: n.y + BORDER_TOP + PORT_TOP }; }
 function outAnchor(n: LogicNode, port: string) {
   const ports = outputs(n.kind);
   const i = Math.max(0, ports.findIndex(p => p.id === port));
-  return { x: n.x + NODE_W, y: n.y + PORT_TOP + i * PORT_GAP };
+  return { x: n.x + NODE_W - BORDER, y: n.y + BORDER_TOP + PORT_TOP + i * PORT_GAP };
 }
 
 function wirePathStr(x1: number, y1: number, x2: number, y2: number): string {
@@ -180,6 +185,15 @@ export default function LogicEditor({ graph, onChange, widgets = [], statevars,
     return dsSignals[ds] ?? [];
   }
 
+  // Flatten every known ds:name into a single list for the fuzzy SignalPicker,
+  // and a hook to lazily load all data sources' signals when a picker opens.
+  function allSignalOptions(): SignalOption[] {
+    const out: SignalOption[] = [];
+    for (const ds of dsOptions) for (const name of signalOptions(ds)) out.push({ ds, name });
+    return out;
+  }
+  function openAllSignals() { dsOptions.forEach(ds => loadSignals(ds)); }
+
   const selected = nodes.find(n => n.id === selectedNode) ?? null;
 
   useEffect(() => {
@@ -520,19 +534,13 @@ export default function LogicEditor({ graph, onChange, widgets = [], statevars,
             )}
 
             {(selected.kind === 'trigger.threshold' || selected.kind === 'trigger.change') && (() => {
-              const { ds, name } = splitRef(selected.params.signal ?? '');
               return (
                 <Fragment>
-                  <div class="wizard-field">
-                    <label>Data source</label>
-                    <SearchableSelect value={ds} options={dsOptions}
-                      onSelect={(newDs) => { loadSignals(newDs); patchParams(selected.id, { signal: `${newDs}:` }); }} />
-                  </div>
                   <div class="wizard-field">
                     <label>Signal</label>
-                    <SearchableSelect value={name} options={signalOptions(ds)}
+                    <SignalPicker value={selected.params.signal ?? ''} options={allSignalOptions()}
-                      onSelect={(sig) => patchParams(selected.id, { signal: `${ds}:${sig}` })}
+                      onOpen={openAllSignals}
-                      placeholder={ds ? 'Search signals…' : 'Select data source first'} />
+                      onChange={(ref) => patchParams(selected.id, { signal: ref })} />
                   </div>
                   {selected.kind === 'trigger.threshold' && (
                     <div class="wizard-field wizard-field-row">
@@ -573,7 +581,7 @@ export default function LogicEditor({ graph, onChange, widgets = [], statevars,
               <ExprField label="Condition" value={selected.params.cond ?? ''}
                 onChange={(v) => patchParams(selected.id, { cond: v })}
                 onInsert={(ds, sig) => insertRef(selected.id, 'cond', ds, sig)}
-                dsOptions={dsOptions} signalOptions={signalOptions} loadSignals={loadSignals}
+                allSignals={allSignalOptions()} onOpenSignals={openAllSignals}
                 hint="True → 'then' port, false → 'else' port. e.g. {stub:level} > 5 && temp < 100. {sys:time}=epoch seconds, {sys:dt}=seconds since the trigger last fired." />
             )}
 
@@ -597,36 +605,29 @@ export default function LogicEditor({ graph, onChange, widgets = [], statevars,
                   <ExprField label="While condition" value={selected.params.cond ?? ''}
                     onChange={(v) => patchParams(selected.id, { cond: v })}
                     onInsert={(ds, sig) => insertRef(selected.id, 'cond', ds, sig)}
-                    dsOptions={dsOptions} signalOptions={signalOptions} loadSignals={loadSignals}
+                    allSignals={allSignalOptions()} onOpenSignals={openAllSignals}
                     hint="Loops the 'body' port while true (capped). e.g. {stub:level} < 90" />
                 )}
                 <p class="hint">Runs the <b>body</b> port repeatedly, then continues on <b>done</b>.</p>
               </Fragment>
             )}
 
-            {selected.kind === 'action.write' && (() => {
+            {selected.kind === 'action.write' && (
-              const { ds, name } = splitRef(selected.params.target ?? '');
+              <Fragment>
-              return (
+                <div class="wizard-field">
-                <Fragment>
+                  <label>Target signal / variable</label>
-                  <div class="wizard-field">
+                  <SignalPicker value={selected.params.target ?? ''} options={allSignalOptions()}
-                    <label>Target data source</label>
+                    onOpen={openAllSignals} allowFreeform
-                    <SearchableSelect value={ds} options={dsOptions}
+                    onChange={(ref) => patchParams(selected.id, { target: ref })} />
-                      onSelect={(newDs) => { loadSignals(newDs); patchParams(selected.id, { target: `${newDs}:` }); }} />
+                  <p class="hint">Pick a signal, or type <code>local:name</code> to write a panel-local variable.</p>
-                  </div>
+                </div>
-                  <div class="wizard-field">
+                <ExprField label="Value (expression)" value={selected.params.expr ?? ''}
-                    <label>Target signal</label>
+                  onChange={(v) => patchParams(selected.id, { expr: v })}
-                    <SearchableSelect value={name} options={signalOptions(ds)}
+                  onInsert={(ds2, sig) => insertRef(selected.id, 'expr', ds2, sig)}
-                      onSelect={(sig) => patchParams(selected.id, { target: `${ds}:${sig}` })}
+                  allSignals={allSignalOptions()} onOpenSignals={openAllSignals}
-                      placeholder={ds ? 'Search signals…' : 'Select data source first'} />
+                  hint="e.g. ({stub:a} - {stub:b}) / {sys:dt} for a rate — or a constant like 42. {sys:time}=epoch seconds, {sys:dt}=seconds since the trigger last fired." />
-                  </div>
+              </Fragment>
-                  <ExprField label="Value (expression)" value={selected.params.expr ?? ''}
+            )}
-                    onChange={(v) => patchParams(selected.id, { expr: v })}
-                    onInsert={(ds2, sig) => insertRef(selected.id, 'expr', ds2, sig)}
-                    dsOptions={dsOptions} signalOptions={signalOptions} loadSignals={loadSignals}
-                    hint="e.g. ({stub:a} - {stub:b}) / {sys:dt} for a rate — or a constant like 42. {sys:time}=epoch seconds, {sys:dt}=seconds since the trigger last fired." />
-                </Fragment>
-              );
-            })()}
 
             {selected.kind === 'action.delay' && (
               <div class="wizard-field">
@@ -647,7 +648,7 @@ export default function LogicEditor({ graph, onChange, widgets = [], statevars,
                 <ExprField label="Value (expression)" value={selected.params.expr ?? ''}
                   onChange={(v) => patchParams(selected.id, { expr: v })}
                   onInsert={(ds2, sig) => insertRef(selected.id, 'expr', ds2, sig)}
-                  dsOptions={dsOptions} signalOptions={signalOptions} loadSignals={loadSignals}
+                  allSignals={allSignalOptions()} onOpenSignals={openAllSignals}
                   hint="Appends this value (with a timestamp) to the array. e.g. {stub:level}, or {sys:time} for the clock." />
               </Fragment>
             )}
@@ -683,7 +684,7 @@ export default function LogicEditor({ graph, onChange, widgets = [], statevars,
                 <ExprField label="Value (expression)" value={selected.params.expr ?? ''}
                   onChange={(v) => patchParams(selected.id, { expr: v })}
                   onInsert={(ds2, sig) => insertRef(selected.id, 'expr', ds2, sig)}
-                  dsOptions={dsOptions} signalOptions={signalOptions} loadSignals={loadSignals}
+                  allSignals={allSignalOptions()} onOpenSignals={openAllSignals}
                   hint="Logs this value to the browser console — handy for debugging a flow." />
               </Fragment>
             )}
@@ -747,7 +748,7 @@ export default function LogicEditor({ graph, onChange, widgets = [], statevars,
                 <DialogFieldsEditor allowInput={false}
                   fields={parseDialogFields(selected)}
                   onChange={(f) => patchParams(selected.id, { fields: JSON.stringify(f) })}
-                  dsOptions={dsOptions} signalOptions={signalOptions} loadSignals={loadSignals} />
+                  allSignals={allSignalOptions()} onOpenSignals={openAllSignals} />
               </Fragment>
             )}
 
@@ -768,7 +769,7 @@ export default function LogicEditor({ graph, onChange, widgets = [], statevars,
                 <DialogFieldsEditor allowInput={true}
                   fields={parseDialogFields(selected)}
                   onChange={(f) => patchParams(selected.id, { fields: JSON.stringify(f) })}
-                  dsOptions={dsOptions} signalOptions={signalOptions} loadSignals={loadSignals} />
+                  allSignals={allSignalOptions()} onOpenSignals={openAllSignals} />
                 <p class="hint">Each <b>input</b> prompts the operator and writes the entered number to its
                   target on OK; each <b>display</b> shows a live value. Cancel aborts the flow.</p>
               </Fragment>
@@ -796,17 +797,15 @@ export default function LogicEditor({ graph, onChange, widgets = [], statevars,
 }
 
 // Expression input with a signal-insert helper and live validation.
-function ExprField({ label, value, onChange, onInsert, dsOptions, signalOptions, loadSignals, hint }: {
+function ExprField({ label, value, onChange, onInsert, allSignals, onOpenSignals, hint }: {
   label: string;
   value: string;
   onChange: (v: string) => void;
   onInsert: (ds: string, sig: string) => void;
-  dsOptions: string[];
+  allSignals: SignalOption[];
-  signalOptions: (ds: string) => string[];
+  onOpenSignals: () => void;
-  loadSignals: (ds: string) => void;
   hint: string;
 }) {
-  const [insDs, setInsDs] = useState('');
   const err = checkExpr(value);
   return (
     <div class="wizard-field">
@@ -816,11 +815,9 @@ function ExprField({ label, value, onChange, onInsert, dsOptions, signalOptions,
         onInput={(e) => onChange((e.target as HTMLInputElement).value)} />
       {err && <p class="wizard-error">{err}</p>}
       <div class="flow-expr-insert">
-        <SearchableSelect value={insDs} options={dsOptions}
+        <SignalPicker value="" options={allSignals} onOpen={onOpenSignals}
-          onSelect={(ds) => { setInsDs(ds); loadSignals(ds); }} placeholder="ds…" />
+          placeholder="+ insert signal"
-        <SearchableSelect value="" options={signalOptions(insDs)}
+          onChange={(ref) => { const s = splitRef(ref); onInsert(s.ds, s.name); }} />
-          onSelect={(sig) => onInsert(insDs, sig)}
-          placeholder={insDs ? '+ insert signal' : 'pick ds first'} />
       </div>
       <p class="hint">{hint}</p>
     </div>
@@ -934,13 +931,12 @@ function parseDialogFields(n: LogicNode): DialogFieldSpec[] {
   return [];
 }
 
-function DialogFieldsEditor({ allowInput, fields, onChange, dsOptions, signalOptions, loadSignals }: {
+function DialogFieldsEditor({ allowInput, fields, onChange, allSignals, onOpenSignals }: {
   allowInput: boolean;
   fields: DialogFieldSpec[];
   onChange: (fields: DialogFieldSpec[]) => void;
-  dsOptions: string[];
+  allSignals: SignalOption[];
-  signalOptions: (ds: string) => string[];
+  onOpenSignals: () => void;
-  loadSignals: (ds: string) => void;
 }) {
   function patch(i: number, patch: Partial<DialogFieldSpec>) {
     onChange(fields.map((f, j) => (j === i ? { ...f, ...patch } : f)));
@@ -953,7 +949,6 @@ function DialogFieldsEditor({ allowInput, fields, onChange, dsOptions, signalOpt
       <label>{allowInput ? 'Fields' : 'Displayed values'}</label>
       {fields.length === 0 && <p class="hint">None yet.</p>}
       {fields.map((f, i) => {
-        const { ds, name } = splitRef(f.target ?? '');
         return (
           <div key={i} class="flow-field-edit">
             <div class="flow-field-head">
@@ -972,11 +967,9 @@ function DialogFieldsEditor({ allowInput, fields, onChange, dsOptions, signalOpt
             {f.type === 'input' ? (
               <Fragment>
                 <div class="flow-row-edit">
-                  <SearchableSelect value={ds} options={dsOptions}
+                  <SignalPicker value={f.target ?? ''} options={allSignals}
-                    onSelect={(newDs) => { loadSignals(newDs); patch(i, { target: `${newDs}:` }); }} placeholder="ds…" />
+                    onOpen={onOpenSignals} allowFreeform placeholder="target signal…"
-                  <SearchableSelect value={name} options={signalOptions(ds)}
+                    onChange={(ref) => patch(i, { target: ref })} />
-                    onSelect={(sig) => patch(i, { target: `${ds}:${sig}` })}
-                    placeholder={ds ? 'signal…' : 'pick ds'} />
                 </div>
                 <input class={`prop-input${checkExpr(f.default ?? '') ? ' prop-input-error' : ''}`}
                   value={f.default ?? ''} placeholder="default value (expression, optional)"

web/src/SignalPicker.tsx

@@ -0,0 +1,113 @@
+import { h } from 'preact';
+import { useState, useMemo } from 'preact/hooks';
+
+// A single fuzzy-finder input for picking a signal as one "ds:name" reference,
+// replacing the old stacked "Data source" + "Signal" select pair. The caller
+// supplies a flattened option list (every ds:name it knows about) and, via
+// onOpen, a hook to lazily load signals for all data sources when the dropdown
+// is first opened. When allowFreeform is set, typing a value that matches no
+// option (e.g. a new srv:/local: variable) can still be committed.
+
+export interface SignalOption { ds: string; name: string; }
+
+export default function SignalPicker({
+  value,
+  options,
+  onChange,
+  onOpen,
+  placeholder = 'Search signals…',
+  allowFreeform = false,
+}: {
+  value: string; // current "ds:name" (or "")
+  options: SignalOption[];
+  onChange: (ref: string) => void;
+  onOpen?: () => void;
+  placeholder?: string;
+  allowFreeform?: boolean;
+}) {
+  const [open, setOpen] = useState(false);
+  const [filter, setFilter] = useState('');
+
+  const filtered = useMemo(() => {
+    const tokens = filter.toLowerCase().split(/\s+/).filter(Boolean);
+    const scored = options
+      .map(o => ({ o, label: `${o.ds}:${o.name}` }))
+      .filter(({ label }) => {
+        const l = label.toLowerCase();
+        return tokens.every(t => l.includes(t));
+      });
+    // Prefer matches where the signal name (not the ds prefix) leads.
+    const f = filter.toLowerCase();
+    scored.sort((a, b) => {
+      const an = a.o.name.toLowerCase().startsWith(f) ? 0 : 1;
+      const bn = b.o.name.toLowerCase().startsWith(f) ? 0 : 1;
+      if (an !== bn) return an - bn;
+      return a.label.localeCompare(b.label);
+    });
+    return scored.slice(0, 200);
+  }, [options, filter]);
+
+  function openDropdown() {
+    setOpen(true);
+    setFilter('');
+    onOpen?.();
+  }
+
+  function commit(ref: string) {
+    onChange(ref);
+    setOpen(false);
+    setFilter('');
+  }
+
+  // A freeform entry is offered when the typed text looks like a usable
+  // reference and is not already an exact option.
+  const freeform = allowFreeform && filter.trim() !== ''
+    && !filtered.some(({ label }) => label === filter.trim());
+
+  return (
+    <div class="search-select">
+      <div class="search-select-trigger" onClick={() => (open ? setOpen(false) : openDropdown())}>
+        {value || <span class="search-select-placeholder">{placeholder}</span>}
+        <span class="search-select-arrow">{open ? '▴' : '▾'}</span>
+      </div>
+      {open && (
+        <div class="search-select-dropdown">
+          <input
+            class="prop-input"
+            autoFocus
+            placeholder="Type to search… (ds:name)"
+            value={filter}
+            onInput={(e) => setFilter((e.target as HTMLInputElement).value)}
+            onClick={(e) => e.stopPropagation()}
+            onKeyDown={(e: KeyboardEvent) => {
+              if (e.key === 'Enter') {
+                e.preventDefault();
+                if (filtered.length > 0) commit(`${filtered[0].o.ds}:${filtered[0].o.name}`);
+                else if (freeform) commit(filter.trim());
+              }
+              if (e.key === 'Escape') { e.preventDefault(); setOpen(false); }
+            }}
+          />
+          <div class="search-select-list">
+            {freeform && (
+              <div class="search-select-item" onClick={() => commit(filter.trim())}>
+                Use “{filter.trim()}”
+              </div>
+            )}
+            {filtered.length === 0 && !freeform && <div class="search-select-item hint">No matches</div>}
+            {filtered.map(({ o, label }) => (
+              <div
+                key={label}
+                class={`search-select-item${label === value ? ' search-select-item-selected' : ''}`}
+                onClick={() => commit(`${o.ds}:${o.name}`)}
+              >
+                {label}
+              </div>
+            ))}
+          </div>
+        </div>
+      )}
+      {open && <div class="search-select-backdrop" onClick={() => setOpen(false)} />}
+    </div>
+  );
+}

web/src/SignalTree.tsx

@@ -1,10 +1,10 @@
 import { h, Fragment } from 'preact';
 import { useState, useEffect, useRef, useMemo } from 'preact/hooks';
 import type { SignalRef, StateVar } from './lib/types';
-import SyntheticWizard from './SyntheticWizard';
 import SyntheticGraphEditor from './SyntheticGraphEditor';
 import GroupsTree from './GroupsTree';
 import ChannelFinderModal from './ChannelFinderModal';
+import SignalPicker from './SignalPicker';
 
 type TreeTab = 'sources' | 'groups';
 type GroupBy = 'datasource' | 'area' | 'system' | 'ioc';
@@ -491,10 +491,11 @@ export default function SignalTree({ onDragStart, width, panelId, statevars, onS
       )}
 
       {showWizard && (
-        <SyntheticWizard
+        <SyntheticGraphEditor
-          currentIfaceId={panelId}
+          create
+          panelId={panelId}
           onClose={() => setShowWizard(false)}
-          onCreated={loadAllSignals}
+          onSaved={loadAllSignals}
         />
       )}
 
@@ -523,24 +524,18 @@ export default function SignalTree({ onDragStart, width, panelId, statevars, onS
             </div>
             <div class="wizard-body">
               <div class="wizard-field">
-                <label>Data Source</label>
+                <label>Signal</label>
-                <select class="prop-select" value={manualDs} onChange={e => setManualDs((e.target as HTMLSelectElement).value)}>
+                <SignalPicker
-                  {Array.from(new Set(allSignals.map(s => s.ds))).map(ds => (
+                  value={manualName ? `${manualDs}:${manualName}` : ''}
-                    <option key={ds} value={ds}>{ds}</option>
+                  options={allSignals}
-                  ))}
+                  allowFreeform
-                  {!allSignals.some(s => s.ds === 'epics') && <option value="epics">epics</option>}
+                  placeholder="Search or type ds:NAME…"
-                </select>
+                  onChange={(ref) => {
-              </div>
+                    const i = ref.indexOf(':');
-              <div class="wizard-field">
+                    if (i < 0) { setManualDs(ref); setManualName(''); }
-                <label>Signal / PV Name</label>
+                    else { setManualDs(ref.slice(0, i)); setManualName(ref.slice(i + 1)); }
-                <input 
+                  }} />
-                  class="prop-input" 
+                <p class="hint">Pick an existing signal, or type <code>epics:MY:PV:NAME</code> to add a new one.</p>
-                  autoFocus
-                  placeholder="e.g. MY:PV:NAME" 
-                  value={manualName}
-                  onInput={e => setManualName((e.target as HTMLInputElement).value)}
-                  onKeyDown={e => e.key === 'Enter' && handleManualAdd()}
-                />
               </div>
             </div>
             <div class="wizard-footer">

web/src/SyntheticGraphEditor.tsx

@@ -1,54 +1,69 @@
 import { h, Fragment } from 'preact';
 import { useState, useEffect, useRef } from 'preact/hooks';
-import SearchableSelect from './SearchableSelect';
+import SignalPicker, { SignalOption } from './SignalPicker';
 import LuaEditor from './LuaEditor';
-import type { InputRef, PipelineNode, SignalDef } from './lib/types';
+import type { SignalDef, SynthGraph, SynthGraphNode } from './lib/types';
 
 interface DataSource { name: string; }
 interface SignalInfo { name: string; }
 
 interface Props {
-  name: string;
+  // Existing signal name (edit mode). Omitted/empty in create mode.
+  name?: string;
+  // When true the editor starts blank and POSTs a new signal on save.
+  create?: boolean;
+  // Interface id used to bind panel-scoped signals when creating.
+  panelId?: string;
   onClose: () => void;
   onSaved: () => void;
 }
 
 // ── Node-type catalogue ──────────────────────────────────────────────────────
-// Mirrors the backend dsp node set (internal/dsp/nodes.go). The combine nodes
+// Mirrors the backend dsp node set (internal/dsp/nodes.go). `arity` describes how
-// (add/subtract/…) and expr take several inputs, which only the FIRST node of a
+// many input ports an op exposes:
-// pipeline receives — see the compile() note below.
+//   fixed n — exactly n inputs (gain=1, subtract/divide=2, …)
+//   min n   — at least n inputs; one spare port appears past the wired count so the
+//             user can keep adding (add/multiply)
+//   named   — the user names each input (expr/lua); ports follow params.vars
+type InArity = { kind: 'fixed'; n: number } | { kind: 'min'; n: number } | { kind: 'named' };
 interface NodeParam { label: string; key: string; type: 'number' | 'text' | 'lua'; default: string; }
-interface OpDef { type: string; label: string; params: NodeParam[]; }
+interface OpDef { type: string; label: string; arity: InArity; params: NodeParam[]; }
 
 const OPS: OpDef[] = [
-  { type: 'gain',           label: 'Gain',           params: [{ label: 'Factor', key: 'gain', type: 'number', default: '1' }] },
+  { type: 'gain',           label: 'Gain',           arity: { kind: 'fixed', n: 1 }, params: [{ label: 'Factor', key: 'gain', type: 'number', default: '1' }] },
-  { type: 'offset',         label: 'Offset',         params: [{ label: 'Offset', key: 'offset', type: 'number', default: '0' }] },
+  { type: 'offset',         label: 'Offset',         arity: { kind: 'fixed', n: 1 }, params: [{ label: 'Offset', key: 'offset', type: 'number', default: '0' }] },
-  { type: 'add',            label: 'Add (Σ inputs)', params: [] },
+  { type: 'add',            label: 'Add (Σ inputs)', arity: { kind: 'min', n: 2 },   params: [] },
-  { type: 'subtract',       label: 'Subtract (a−b)', params: [] },
+  { type: 'subtract',       label: 'Subtract (a−b)', arity: { kind: 'fixed', n: 2 }, params: [] },
-  { type: 'multiply',       label: 'Multiply (Π)',   params: [] },
+  { type: 'multiply',       label: 'Multiply (Π)',   arity: { kind: 'min', n: 2 },   params: [] },
-  { type: 'divide',         label: 'Divide (a÷b)',   params: [] },
+  { type: 'divide',         label: 'Divide (a÷b)',   arity: { kind: 'fixed', n: 2 }, params: [] },
-  { type: 'moving_average', label: 'Moving Average', params: [{ label: 'Window (n)', key: 'window', type: 'number', default: '10' }] },
+  { type: 'moving_average', label: 'Moving Average', arity: { kind: 'fixed', n: 1 }, params: [{ label: 'Window (n)', key: 'window', type: 'number', default: '10' }] },
-  { type: 'rms',            label: 'RMS',            params: [{ label: 'Window (n)', key: 'window', type: 'number', default: '10' }] },
+  { type: 'rms',            label: 'RMS',            arity: { kind: 'fixed', n: 1 }, params: [{ label: 'Window (n)', key: 'window', type: 'number', default: '10' }] },
-  { type: 'lowpass',        label: 'Low-pass',       params: [
+  { type: 'lowpass',        label: 'Low-pass',       arity: { kind: 'fixed', n: 1 }, params: [
     { label: 'Cutoff freq (Hz)', key: 'freq', type: 'number', default: '1' },
     { label: 'Order (1–8)', key: 'order', type: 'number', default: '1' },
   ]},
-  { type: 'derivative',     label: 'Derivative',     params: [] },
+  { type: 'derivative',     label: 'Derivative',     arity: { kind: 'fixed', n: 1 }, params: [] },
-  { type: 'integrate',      label: 'Integrate',      params: [] },
+  { type: 'integrate',      label: 'Integrate',      arity: { kind: 'fixed', n: 1 }, params: [] },
-  { type: 'clamp',          label: 'Clamp',          params: [{ label: 'Min', key: 'min', type: 'number', default: '0' }, { label: 'Max', key: 'max', type: 'number', default: '100' }] },
+  { type: 'clamp',          label: 'Clamp',          arity: { kind: 'fixed', n: 1 }, params: [{ label: 'Min', key: 'min', type: 'number', default: '0' }, { label: 'Max', key: 'max', type: 'number', default: '100' }] },
-  { type: 'threshold',      label: 'Threshold',      params: [
+  { type: 'threshold',      label: 'Threshold',      arity: { kind: 'fixed', n: 1 }, params: [
     { label: 'Threshold', key: 'threshold', type: 'number', default: '0' },
     { label: 'High output', key: 'high', type: 'number', default: '1' },
     { label: 'Low output', key: 'low', type: 'number', default: '0' },
   ]},
-  { type: 'expr',           label: 'Formula',        params: [{ label: 'Expression (a,b,c,d = inputs)', key: 'expr', type: 'text', default: 'a * 1.0' }] },
+  { type: 'expr',           label: 'Formula',        arity: { kind: 'named' }, params: [{ label: 'Expression', key: 'expr', type: 'text', default: 'a + b' }] },
-  { type: 'lua',            label: 'Lua Script',     params: [{ label: 'Script (a,b,c,d = inputs)', key: 'script', type: 'lua', default: 'return a' }] },
+  { type: 'lua',            label: 'Lua Script',     arity: { kind: 'named' }, params: [{ label: 'Script', key: 'script', type: 'lua', default: 'return a + b' }] },
 ];
 const OP_BY_TYPE = new Map(OPS.map(o => [o.type, o]));
 function opLabel(type: string): string { return OP_BY_TYPE.get(type)?.label ?? type; }
 function opParamDefs(type: string): NodeParam[] { return OP_BY_TYPE.get(type)?.params ?? []; }
+function opArity(type?: string): InArity { return OP_BY_TYPE.get(type ?? '')?.arity ?? { kind: 'fixed', n: 1 }; }
 
-// ── Graph model (UI only — compiled to SignalDef on save) ───────────────────
+// Default input names a,b,c,… for named (expr/lua) nodes.
+function letters(n: number): string[] {
+  return Array.from({ length: Math.max(1, n) }, (_, i) => String.fromCharCode(97 + i));
+}
+
+// ── Graph model (UI only — compiled to SynthGraph on save) ──────────────────
 type NodeKind = 'source' | 'op' | 'output';
 interface GNode {
   id: string;
@@ -58,9 +73,10 @@ interface GNode {
   ds?: string;      // source
   signal?: string;  // source
   op?: string;      // op type
-  params?: Record<string, any>; // op
+  params?: Record<string, any>; // op (named ops carry params.vars: string[])
 }
-interface GWire { from: string; to: string; }
+// A wire terminates on a specific input port (index) of the target node.
+interface GWire { from: string; to: string; toPort: number; }
 interface Graph { nodes: GNode[]; wires: GWire[]; }
 
 // ── Geometry (rem-based, like the logic editor) ─────────────────────────────
@@ -69,23 +85,75 @@ const REM = (() => {
   return parseFloat(getComputedStyle(document.documentElement).fontSize) || 16;
 })();
 const NODE_W = 10 * REM;
-const PORT_TOP = 1.4 * REM;
+const PORT_TOP = 1.7 * REM;   // y of the first input/output port row
+const PORT_GAP = 1.25 * REM;  // vertical spacing between stacked input ports
 const PORT_R = 0.375 * REM;
+// Ports are absolutely positioned inside the node's padding box, which is offset
+// from the node's border-box origin (node.x/node.y) by the node borders: a 3px
+// colored accent on top and 1px on the sides. Wire anchors must add the same
+// offsets or they land at the top edge of the port circle instead of its center.
+const BORDER = 1;
+const BORDER_TOP = 3;
 
 function genId(): string { return 'g_' + Math.random().toString(36).slice(2, 9); }
-function hasInput(k: NodeKind): boolean { return k !== 'source'; }
 function hasOutput(k: NodeKind): boolean { return k !== 'output'; }
-function inAnchor(n: GNode) { return { x: n.x, y: n.y + PORT_TOP }; }
+
-function outAnchor(n: GNode) { return { x: n.x + NODE_W, y: n.y + PORT_TOP }; }
+// Number of input ports a node currently shows.
+function inPortCount(n: GNode, wires: GWire[]): number {
+  if (n.kind === 'source') return 0;
+  if (n.kind === 'output') return 1;
+  const ar = opArity(n.op);
+  if (ar.kind === 'fixed') return ar.n;
+  if (ar.kind === 'named') return Math.max(1, (n.params?.vars as string[] | undefined)?.length ?? 0);
+  // min: expose one spare port beyond the highest wired index so the user can add more.
+  const wired = wires.filter(w => w.to === n.id).length;
+  return Math.max(ar.n, wired + 1);
+}
+function inAnchor(n: GNode, port: number) {
+  return { x: n.x + BORDER, y: n.y + BORDER_TOP + PORT_TOP + port * PORT_GAP };
+}
+function outAnchor(n: GNode) { return { x: n.x + NODE_W - BORDER, y: n.y + BORDER_TOP + PORT_TOP }; }
+function nodeMinHeight(n: GNode, wires: GWire[]): number {
+  const nIn = Math.max(1, inPortCount(n, wires));
+  return BORDER_TOP + PORT_TOP + nIn * PORT_GAP;
+}
 function wirePathStr(x1: number, y1: number, x2: number, y2: number): string {
   const dx = Math.max(40, Math.abs(x2 - x1) / 2);
   return `M ${x1} ${y1} C ${x1 + dx} ${y1}, ${x2 - dx} ${y2}, ${x2} ${y2}`;
 }
 
-// Build an initial graph by laying out an existing SignalDef: sources stacked on
+// Label shown beside an input port (named ops show their var name).
-// the left, the linear pipeline as a row of op nodes, output on the right.
+function portLabel(n: GNode, port: number): string {
+  if (opArity(n.op).kind === 'named') {
+    const vars = (n.params?.vars as string[] | undefined) ?? [];
+    return vars[port] ?? '';
+  }
+  return '';
+}
+
+// Build an initial graph from an existing SignalDef. Prefer the stored DAG; fall
+// back to laying out the legacy linear Inputs+Pipeline form.
 function buildInitial(def: SignalDef): Graph {
-  const inputs: InputRef[] = def.inputs && def.inputs.length > 0
+  if (def.graph && def.graph.nodes.length > 0) {
+    const nodes: GNode[] = def.graph.nodes.map((n, i) => ({
+      id: n.id,
+      kind: n.kind,
+      x: n.x ?? (2 + (i % 3) * 12) * REM,
+      y: n.y ?? (2 + Math.floor(i / 3) * 5) * REM,
+      ds: n.ds,
+      signal: n.signal,
+      op: n.op,
+      params: n.params ? { ...n.params } : undefined,
+    }));
+    const wires: GWire[] = [];
+    for (const n of def.graph.nodes) {
+      (n.inputs ?? []).forEach((from, port) => wires.push({ from, to: n.id, toPort: port }));
+    }
+    return { nodes, wires };
+  }
+
+  // Legacy linear layout: sources stacked left, pipeline a row of op nodes, output right.
+  const inputs = def.inputs && def.inputs.length > 0
     ? def.inputs
     : (def.ds && def.signal ? [{ ds: def.ds, signal: def.signal }] : []);
   const pipeline = def.pipeline ?? [];
@@ -99,57 +167,108 @@ function buildInitial(def: SignalDef): Graph {
   });
   const opIds = pipeline.map((nd, i) => {
     const id = genId();
-    nodes.push({ id, kind: 'op', x: (15 + i * 12) * REM, y: 3 * REM, op: nd.type, params: { ...nd.params } });
+    const params: Record<string, any> = { ...nd.params };
+    // The head op received every source as a,b,c,…; later ops a single input.
+    if (opArity(nd.type).kind === 'named') params.vars = letters(i === 0 ? srcIds.length : 1);
+    nodes.push({ id, kind: 'op', x: (15 + i * 12) * REM, y: 3 * REM, op: nd.type, params });
     return id;
   });
   const outId = genId();
   nodes.push({ id: outId, kind: 'output', x: (15 + pipeline.length * 12) * REM, y: 3 * REM });
 
   const headId = opIds[0] ?? outId;
-  srcIds.forEach(s => wires.push({ from: s, to: headId }));
+  srcIds.forEach((s, i) => wires.push({ from: s, to: headId, toPort: i }));
-  for (let i = 0; i < opIds.length - 1; i++) wires.push({ from: opIds[i], to: opIds[i + 1] });
+  for (let i = 0; i < opIds.length - 1; i++) wires.push({ from: opIds[i], to: opIds[i + 1], toPort: 0 });
-  if (opIds.length > 0) wires.push({ from: opIds[opIds.length - 1], to: outId });
+  if (opIds.length > 0) wires.push({ from: opIds[opIds.length - 1], to: outId, toPort: 0 });
 
   return { nodes, wires };
 }
 
-// Compile the visual graph back into the backend's linear form. The pipeline is
+// Compile the visual graph into the backend DAG form. Each op/output node's
-// a single chain ending at the output; the head node receives every source
+// inputs are its wires ordered by target port index.
-// signal (inputs[0]=a, inputs[1]=b, …), every later node the previous output.
+function compile(g: Graph): SynthGraph {
-function compile(g: Graph): { inputs?: InputRef[]; pipeline?: PipelineNode[]; error?: string } {
   const output = g.nodes.find(n => n.kind === 'output');
-  if (!output) return { error: 'missing output node' };
+  const nodes: SynthGraphNode[] = g.nodes.map(n => {
-  const byId = new Map(g.nodes.map(n => [n.id, n]));
+    const inputs = g.wires
-  const upstream = (id: string) => g.wires.filter(w => w.to === id).map(w => byId.get(w.from)).filter(Boolean) as GNode[];
+      .filter(w => w.to === n.id)
+      .slice()
+      .sort((a, b) => a.toPort - b.toPort)
+      .map(w => w.from);
+    if (n.kind === 'source') return { id: n.id, kind: 'source', ds: n.ds, signal: n.signal, x: n.x, y: n.y };
+    if (n.kind === 'output') return { id: n.id, kind: 'output', inputs, x: n.x, y: n.y };
+    return { id: n.id, kind: 'op', op: n.op, params: n.params, inputs, x: n.x, y: n.y };
+  });
+  return { nodes, output: output?.id ?? '' };
+}
 
-  const chain: GNode[] = [];
+// Detect a cycle in the graph (Kahn count over input edges).
-  const seen = new Set<string>();
+function hasCycle(g: Graph): boolean {
-  let cur: GNode = output;
+  const indeg = new Map<string, number>();
-  for (;;) {
+  const succ = new Map<string, string[]>();
-    if (seen.has(cur.id)) return { error: 'the graph contains a cycle' };
+  for (const n of g.nodes) indeg.set(n.id, 0);
-    seen.add(cur.id);
+  for (const w of g.wires) {
-    const ups = upstream(cur.id);
+    if (!indeg.has(w.to) || !indeg.has(w.from)) continue;
-    const opUps = ups.filter(n => n.kind === 'op');
+    indeg.set(w.to, (indeg.get(w.to) ?? 0) + 1);
-    const srcUps = ups.filter(n => n.kind === 'source');
+    succ.set(w.from, [...(succ.get(w.from) ?? []), w.to]);
-    if (opUps.length > 1) return { error: 'a node may have only one upstream node — the pipeline must be a single chain' };
+  }
-    if (opUps.length === 1) {
+  const queue = g.nodes.filter(n => (indeg.get(n.id) ?? 0) === 0).map(n => n.id);
-      if (srcUps.length > 0) return { error: 'only the first processing node may take input signals directly' };
+  let visited = 0;
-      chain.unshift(opUps[0]);
+  while (queue.length) {
-      cur = opUps[0];
+    const id = queue.shift()!;
+    visited++;
+    for (const s of succ.get(id) ?? []) {
+      indeg.set(s, (indeg.get(s) ?? 0) - 1);
+      if ((indeg.get(s) ?? 0) === 0) queue.push(s);
+    }
+  }
+  return visited !== g.nodes.length;
+}
+
+// Validate the graph; return a per-node error map plus the first message found.
+function validate(g: Graph): { errors: Map<string, string>; first?: string } {
+  const errors = new Map<string, string>();
+  const set = (id: string, msg: string) => { if (!errors.has(id)) errors.set(id, msg); };
+
+  if (!g.nodes.some(n => n.kind === 'output')) {
+    return { errors, first: 'missing output node' };
+  }
+
+  for (const n of g.nodes) {
+    const ports = new Set(g.wires.filter(w => w.to === n.id).map(w => w.toPort));
+    if (n.kind === 'source') {
+      if (!n.ds || !n.signal) set(n.id, 'pick a data source and signal');
       continue;
     }
-    // Reached the head of the chain: its source upstreams become the inputs.
+    if (n.kind === 'output') {
-    if (srcUps.length === 0) {
+      if (!ports.has(0)) set(n.id, 'connect a value to the output');
-      return { error: cur.kind === 'output' ? 'connect at least one signal to the output' : 'the first node has no input signals' };
+      continue;
+    }
+    const ar = opArity(n.op);
+    if (ar.kind === 'fixed' || ar.kind === 'named') {
+      const cnt = ar.kind === 'fixed' ? ar.n : ((n.params?.vars as string[] | undefined)?.length ?? 0);
+      if (cnt === 0) { set(n.id, 'add at least one named input'); continue; }
+      for (let i = 0; i < cnt; i++) {
+        if (!ports.has(i)) { set(n.id, 'all inputs must be connected'); break; }
+      }
+    } else {
+      // min: needs ≥ ar.n contiguous inputs starting at port 0.
+      const cnt = ports.size;
+      if (cnt < ar.n) { set(n.id, `needs at least ${ar.n} inputs`); continue; }
+      for (let i = 0; i < cnt; i++) {
+        if (!ports.has(i)) { set(n.id, 'inputs have a gap — reconnect them'); break; }
+      }
     }
-    const inputs = srcUps
-      .slice()
-      .sort((a, b) => a.y - b.y)
-      .map(n => ({ ds: n.ds || '', signal: n.signal || '' }));
-    if (inputs.some(i => !i.ds || !i.signal)) return { error: 'every input signal needs a data source and a signal' };
-    const pipeline = chain.map(n => ({ type: n.op!, params: n.params ?? {} }));
-    return { inputs, pipeline };
   }
+
+  let first: string | undefined;
+  if (hasCycle(g)) first = 'the graph contains a cycle';
+  if (!first) {
+    for (const n of g.nodes) {
+      const m = errors.get(n.id);
+      if (m) { first = `${n.kind === 'op' ? opLabel(n.op ?? '') : n.kind}: ${m}`; break; }
+    }
+  }
+  return { errors, first };
 }
 
 function nodeSummary(n: GNode): string {
@@ -170,7 +289,7 @@ function nodeSummary(n: GNode): string {
   }
 }
 
-export default function SyntheticGraphEditor({ name, onClose, onSaved }: Props) {
+export default function SyntheticGraphEditor({ name, create, panelId, onClose, onSaved }: Props) {
   const [def, setDef] = useState<SignalDef | null>(null);
   const [graph, setGraph] = useState<Graph>({ nodes: [], wires: [] });
   const [selected, setSelected] = useState<string | null>(null);
@@ -179,6 +298,15 @@ export default function SyntheticGraphEditor({ name, onClose, onSaved }: Props)
   const [saving, setSaving] = useState(false);
   const [error, setError] = useState('');
 
+  // Identity fields — editable only when creating a new signal.
+  const [newName, setNewName] = useState('');
+  const [visibility, setVisibility] = useState<'panel' | 'user' | 'global'>(panelId ? 'panel' : 'user');
+  const [unit, setUnit] = useState('');
+  const [desc, setDesc] = useState('');
+  const [dispLow, setDispLow] = useState('0');
+  const [dispHigh, setDispHigh] = useState('100');
+  const sigName = create ? newName.trim() : (name ?? '');
+
   const [dataSources, setDataSources] = useState<string[]>([]);
   const [dsSignals, setDsSignals] = useState<Record<string, string[]>>({});
 
@@ -214,18 +342,38 @@ export default function SyntheticGraphEditor({ name, onClose, onSaved }: Props)
     } catch {}
   }
 
+  // Flatten every known ds:name into a single list for the fuzzy SignalPicker,
+  // and a hook to lazily load all data sources' signals when a picker opens.
+  function allSignalOptions(): SignalOption[] {
+    const out: SignalOption[] = [];
+    for (const ds of dataSources) for (const name of (dsSignals[ds] ?? [])) out.push({ ds, name });
+    return out;
+  }
+  function openAllSignals() { dataSources.forEach(ds => loadSignals(ds)); }
+
   useEffect(() => {
-    fetch(`/api/v1/synthetic/${encodeURIComponent(name)}`)
+    if (create) {
+      const blank: SignalDef = { name: '', inputs: [], pipeline: [], meta: {} };
+      setDef(blank);
+      setGraph(buildInitial(blank));
+      setLoading(false);
+      return;
+    }
+    fetch(`/api/v1/synthetic/${encodeURIComponent(name ?? '')}`)
       .then(r => r.ok ? r.json() : Promise.reject(r.statusText))
       .then((d: SignalDef) => {
         setDef(d);
+        setUnit(d.meta?.unit ?? '');
+        setDesc(d.meta?.description ?? '');
+        setDispLow(String(d.meta?.displayLow ?? '0'));
+        setDispHigh(String(d.meta?.displayHigh ?? '100'));
         const g = buildInitial(d);
         setGraph(g);
         g.nodes.forEach(n => { if (n.kind === 'source' && n.ds) loadSignals(n.ds); });
       })
       .catch(e => setError(String(e)))
       .finally(() => setLoading(false));
-  }, [name]);
+  }, [name, create]);
 
   // ── History ────────────────────────────────────────────────────────────────
   function pushUndo() {
@@ -263,6 +411,7 @@ export default function SyntheticGraphEditor({ name, onClose, onSaved }: Props)
   function addOp(op: OpDef, x?: number, y?: number) {
     const params: Record<string, any> = {};
     for (const p of op.params) params[p.key] = p.type === 'number' ? parseFloat(p.default) : p.default;
+    if (op.arity.kind === 'named') params.vars = ['a', 'b'];
     const node: GNode = { id: genId(), kind: 'op', op: op.type, params, x: x ?? (14 + (graph.nodes.length % 4) * 3) * REM, y: y ?? (3 + (graph.nodes.length % 4) * 2) * REM };
     commit({ nodes: [...graph.nodes, node], wires: graph.wires });
     setSelected(node.id); setSelectedWire(null);
@@ -281,8 +430,45 @@ export default function SyntheticGraphEditor({ name, onClose, onSaved }: Props)
       wires: graph.wires,
     });
   }
+  // Named-input (expr/lua) variable list editing.
+  function addNamedVar(id: string) {
+    commit({
+      nodes: graph.nodes.map(n => {
+        if (n.id !== id) return n;
+        const vars = [...((n.params?.vars as string[] | undefined) ?? [])];
+        vars.push(letters(vars.length + 1)[vars.length]);
+        return { ...n, params: { ...n.params, vars } };
+      }),
+      wires: graph.wires,
+    });
+  }
+  function renameNamedVar(id: string, idx: number, value: string) {
+    commit({
+      nodes: graph.nodes.map(n => {
+        if (n.id !== id) return n;
+        const vars = [...((n.params?.vars as string[] | undefined) ?? [])];
+        vars[idx] = value;
+        return { ...n, params: { ...n.params, vars } };
+      }),
+      wires: graph.wires,
+    });
+  }
+  function removeNamedVar(id: string, idx: number) {
+    const nodes = graph.nodes.map(n => {
+      if (n.id !== id) return n;
+      const vars = [...((n.params?.vars as string[] | undefined) ?? [])];
+      vars.splice(idx, 1);
+      return { ...n, params: { ...n.params, vars } };
+    });
+    // Drop the wire at the removed port and shift higher ports down by one.
+    const wires = graph.wires
+      .filter(w => !(w.to === id && w.toPort === idx))
+      .map(w => (w.to === id && w.toPort > idx ? { ...w, toPort: w.toPort - 1 } : w));
+    commit({ nodes, wires });
+  }
   function moveNode(id: string, x: number, y: number, record: boolean) {
-    commit({ nodes: graph.nodes.map(n => (n.id === id ? { ...n, x, y } : n)), wires: graph.wires }, record);
+    const g = graphRef.current;
+    commit({ nodes: g.nodes.map(n => (n.id === id ? { ...n, x, y } : n)), wires: g.wires }, record);
   }
   function deleteNode(id: string) {
     const n = graph.nodes.find(x => x.id === id);
@@ -290,19 +476,29 @@ export default function SyntheticGraphEditor({ name, onClose, onSaved }: Props)
     commit({ nodes: graph.nodes.filter(x => x.id !== id), wires: graph.wires.filter(w => w.from !== id && w.to !== id) });
     if (selected === id) setSelected(null);
   }
-  function addWire(from: string, to: string) {
+  function addWire(from: string, to: string, toPort: number) {
     if (from === to) return;
     const fn = graph.nodes.find(n => n.id === from);
     const tn = graph.nodes.find(n => n.id === to);
-    if (!fn || !tn || !hasOutput(fn.kind) || !hasInput(tn.kind)) return;
+    if (!fn || !tn || !hasOutput(fn.kind) || tn.kind === 'source') return;
-    if (graph.wires.some(w => w.from === from && w.to === to)) return;
+    // One wire per input port: replace any existing wire on that port.
-    commit({ nodes: graph.nodes, wires: [...graph.wires, { from, to }] });
+    const wires = graph.wires.filter(w => !(w.to === to && w.toPort === toPort));
+    if (wires.some(w => w.from === from && w.to === to && w.toPort === toPort)) return;
+    commit({ nodes: graph.nodes, wires: [...wires, { from, to, toPort }] });
   }
   function deleteWire(idx: number) {
     commit({ nodes: graph.nodes, wires: graph.wires.filter((_, i) => i !== idx) });
     if (selectedWire === idx) setSelectedWire(null);
   }
 
+  // The lowest input port of `target` not yet wired (for node-body drops).
+  function firstFreePort(target: GNode): number {
+    const used = new Set(graphRef.current.wires.filter(w => w.to === target.id).map(w => w.toPort));
+    const cnt = inPortCount(target, graphRef.current.wires);
+    for (let i = 0; i < cnt; i++) if (!used.has(i)) return i;
+    return cnt; // all full — append (min-arity nodes grow)
+  }
+
   // ── Pointer / drag / wire ──────────────────────────────────────────────────
   function toCanvas(e: MouseEvent) {
     const el = canvasRef.current!;
@@ -314,48 +510,52 @@ export default function SyntheticGraphEditor({ name, onClose, onSaved }: Props)
     const p = toCanvas(e);
     dragNode.current = { id: node.id, dx: p.x - node.x, dy: p.y - node.y, pushed: false };
     setSelected(node.id); setSelectedWire(null);
-    window.addEventListener('mousemove', onNodeDragMove);
-    window.addEventListener('mouseup', onNodeDragUp);
-  }
-  function onNodeDragMove(e: MouseEvent) {
-    const d = dragNode.current;
-    if (!d) return;
-    const p = toCanvas(e);
-    const record = !d.pushed;
-    d.pushed = true;
-    moveNode(d.id, Math.max(0, p.x - d.dx), Math.max(0, p.y - d.dy), record);
-  }
-  function onNodeDragUp() {
-    dragNode.current = null;
-    window.removeEventListener('mousemove', onNodeDragMove);
-    window.removeEventListener('mouseup', onNodeDragUp);
   }
   function startWire(e: MouseEvent, node: GNode) {
     e.stopPropagation();
     const p = toCanvas(e);
     setPendingWire({ from: node.id, x: p.x, y: p.y });
-    window.addEventListener('mousemove', onWireMove);
-    window.addEventListener('mouseup', onWireUp);
-  }
-  function onWireMove(e: MouseEvent) {
-    const cur = pendingRef.current;
-    if (!cur) return;
-    const p = toCanvas(e);
-    setPendingWire({ ...cur, x: p.x, y: p.y });
   }
   function endWire() {
     pendingRef.current = null;
-    window.removeEventListener('mousemove', onWireMove);
-    window.removeEventListener('mouseup', onWireUp);
     setPendingWire(null);
   }
-  function onWireUp() { endWire(); }
+  function finishWire(target: GNode, port: number) {
-  function finishWire(target: GNode) {
     const cur = pendingRef.current;
-    if (cur && hasInput(target.kind)) addWire(cur.from, target.id);
+    if (cur && target.kind !== 'source') addWire(cur.from, target.id, port);
     endWire();
   }
 
+  // Single mount-time pointer handler. Reads live drag/wire state from refs so it
+  // never goes stale across re-renders — fixes the "can't drop a dragged node" bug.
+  useEffect(() => {
+    function onMove(e: MouseEvent) {
+      const d = dragNode.current;
+      if (d) {
+        const p = toCanvas(e);
+        const record = !d.pushed;
+        d.pushed = true;
+        moveNode(d.id, Math.max(0, p.x - d.dx), Math.max(0, p.y - d.dy), record);
+        return;
+      }
+      const cur = pendingRef.current;
+      if (cur) {
+        const p = toCanvas(e);
+        setPendingWire({ ...cur, x: p.x, y: p.y });
+      }
+    }
+    function onUp() {
+      dragNode.current = null;
+      if (pendingRef.current) endWire();
+    }
+    window.addEventListener('mousemove', onMove);
+    window.addEventListener('mouseup', onUp);
+    return () => {
+      window.removeEventListener('mousemove', onMove);
+      window.removeEventListener('mouseup', onUp);
+    };
+  }, []);
+
   // ── Palette drag-and-drop ──────────────────────────────────────────────────
   const DRAG_MIME = 'application/x-uopi-synth-op';
   function onCanvasDragOver(e: DragEvent) {
@@ -392,20 +592,44 @@ export default function SyntheticGraphEditor({ name, onClose, onSaved }: Props)
 
   const byId = new Map(graph.nodes.map(n => [n.id, n]));
   const sel = graph.nodes.find(n => n.id === selected) ?? null;
-  const compiled = compile(graph);
+  const { errors: nodeErrors, first: validationError } = validate(graph);
 
   async function handleSave() {
     if (!def) return;
-    if (compiled.error) { setError(compiled.error); return; }
+    if (create && !sigName) { setError('Enter a name for the new signal.'); return; }
+    if (validationError) { setError(validationError); return; }
     setSaving(true);
     setError('');
     try {
-      const body = { ...def, inputs: compiled.inputs, pipeline: compiled.pipeline, ds: undefined, signal: undefined };
+      const meta = {
-      const res = await fetch(`/api/v1/synthetic/${encodeURIComponent(name)}`, {
+        ...def.meta,
-        method: 'PUT',
+        unit: unit || undefined,
-        headers: { 'Content-Type': 'application/json' },
+        description: desc || undefined,
-        body: JSON.stringify(body),
+        displayLow: parseFloat(dispLow),
-      });
+        displayHigh: parseFloat(dispHigh),
+      };
+      const body: any = {
+        ...def,
+        name: sigName,
+        graph: compile(graph),
+        meta,
+        inputs: undefined,
+        pipeline: undefined,
+        ds: undefined,
+        signal: undefined,
+      };
+      if (create) {
+        body.visibility = visibility;
+        if (visibility === 'panel' && panelId) body.panel = panelId;
+      }
+      const res = await fetch(
+        create ? '/api/v1/synthetic' : `/api/v1/synthetic/${encodeURIComponent(sigName)}`,
+        {
+          method: create ? 'POST' : 'PUT',
+          headers: { 'Content-Type': 'application/json' },
+          body: JSON.stringify(body),
+        },
+      );
       if (!res.ok) {
         const j = await res.json().catch(() => ({ error: res.statusText }));
         throw new Error(j.error ?? res.statusText);
@@ -421,14 +645,15 @@ export default function SyntheticGraphEditor({ name, onClose, onSaved }: Props)
 
   function nodeClass(n: GNode): string {
     const cat = n.kind === 'source' ? 'trigger' : n.kind === 'output' ? 'action' : 'flow';
-    return `flow-node flow-node-${cat}${selected === n.id ? ' flow-node-selected' : ''}`;
+    const err = nodeErrors.has(n.id) ? ' flow-node-error' : '';
+    return `flow-node flow-node-${cat}${selected === n.id ? ' flow-node-selected' : ''}${err}`;
   }
 
   return (
     <div class="wizard-backdrop" onClick={onClose}>
       <div class="synth-graph" onClick={(e) => e.stopPropagation()}>
         <div class="wizard-header">
-          <span>Synthetic Signal — {name}</span>
+          <span>Synthetic Signal{create ? ' — new' : ` — ${name}`}</span>
           <button class="icon-btn" onClick={onClose}>✕</button>
         </div>
 
@@ -452,8 +677,8 @@ export default function SyntheticGraphEditor({ name, onClose, onSaved }: Props)
                   onClick={() => addOp(op)}>{op.label}</button>
               ))}
               <div class="flow-palette-hint hint">
-                Wire input signals into the first operation, chain operations, and connect the
+                Wire signals into each operation's input ports, then connect the result
-                last one to <b>Output</b>. The first node receives every input as <code>a,b,c,d</code>.
+                to <b>Output</b>. Formula / Lua nodes name their own inputs.
               </div>
             </div>
 
@@ -466,7 +691,7 @@ export default function SyntheticGraphEditor({ name, onClose, onSaved }: Props)
                   {graph.wires.map((w, idx) => {
                     const a = byId.get(w.from); const b = byId.get(w.to);
                     if (!a || !b) return null;
-                    const p1 = outAnchor(a); const p2 = inAnchor(b);
+                    const p1 = outAnchor(a); const p2 = inAnchor(b, w.toPort);
                     return (
                       <path key={idx}
                         class={`flow-wire${selectedWire === idx ? ' flow-wire-selected' : ''}`}
@@ -482,54 +707,113 @@ export default function SyntheticGraphEditor({ name, onClose, onSaved }: Props)
                   })()}
                 </svg>
 
-                {graph.nodes.map(node => (
+                {graph.nodes.map(node => {
-                  <div key={node.id}
+                  const nIn = inPortCount(node, graph.wires);
-                    class={nodeClass(node)}
+                  return (
-                    style={`left:${node.x}px; top:${node.y}px; width:${NODE_W}px;`}
+                    <div key={node.id}
-                    onMouseDown={(e) => startNodeDrag(e, node)}
+                      class={nodeClass(node)}
-                    onMouseUp={() => { if (pendingRef.current) finishWire(node); }}>
+                      style={`left:${node.x}px; top:${node.y}px; width:${NODE_W}px; min-height:${nodeMinHeight(node, graph.wires)}px;`}
-                    <div class="flow-node-header">
+                      onMouseDown={(e) => startNodeDrag(e, node)}
-                      <span class="flow-node-title">{node.kind === 'source' ? 'Signal' : node.kind === 'output' ? 'Output' : opLabel(node.op ?? '')}</span>
+                      onMouseUp={() => { if (pendingRef.current) finishWire(node, firstFreePort(node)); }}>
-                      {node.kind !== 'output' && (
+                      <div class="flow-node-header">
-                        <button class="flow-node-del" title="Delete node"
+                        <span class="flow-node-title">{node.kind === 'source' ? 'Signal' : node.kind === 'output' ? 'Output' : opLabel(node.op ?? '')}</span>
-                          onMouseDown={(e) => e.stopPropagation()}
+                        {node.kind !== 'output' && (
-                          onClick={(e) => { e.stopPropagation(); deleteNode(node.id); }}>✕</button>
+                          <button class="flow-node-del" title="Delete node"
+                            onMouseDown={(e) => e.stopPropagation()}
+                            onClick={(e) => { e.stopPropagation(); deleteNode(node.id); }}>✕</button>
+                        )}
+                      </div>
+                      <div class="flow-node-body hint">{nodeSummary(node)}</div>
+
+                      {Array.from({ length: nIn }, (_, port) => {
+                        const label = portLabel(node, port);
+                        return (
+                          <Fragment key={port}>
+                            <div class="flow-port flow-port-in" title={label || `Input ${port + 1}`}
+                              style={`top:${PORT_TOP + port * PORT_GAP - PORT_R}px; left:${-PORT_R}px;`}
+                              onMouseDown={(e) => e.stopPropagation()}
+                              onMouseUp={(e) => { e.stopPropagation(); finishWire(node, port); }} />
+                            {label && (
+                              <span class="flow-port-label-in"
+                                style={`top:${PORT_TOP + port * PORT_GAP - 0.6 * REM}px;`}>{label}</span>
+                            )}
+                          </Fragment>
+                        );
+                      })}
+                      {hasOutput(node.kind) && (
+                        <div class="flow-port flow-port-out" title="Output"
+                          style={`top:${PORT_TOP - PORT_R}px; right:${-PORT_R}px;`}
+                          onMouseDown={(e) => startWire(e, node)} />
                       )}
                     </div>
-                    <div class="flow-node-body hint">{nodeSummary(node)}</div>
+                  );
-
+                })}
-                    {hasInput(node.kind) && (
-                      <div class="flow-port flow-port-in" title="Input"
-                        style={`top:${PORT_TOP - PORT_R}px; left:${-PORT_R}px;`}
-                        onMouseDown={(e) => e.stopPropagation()}
-                        onMouseUp={(e) => { e.stopPropagation(); finishWire(node); }} />
-                    )}
-                    {hasOutput(node.kind) && (
-                      <div class="flow-port flow-port-out" title="Output"
-                        style={`top:${PORT_TOP - PORT_R}px; right:${-PORT_R}px;`}
-                        onMouseDown={(e) => startWire(e, node)} />
-                    )}
-                  </div>
-                ))}
               </div>
             </div>
 
             <div class="flow-inspector">
-              {!sel && <div class="hint">Select a node to edit it, or add one from the palette.</div>}
+              {!sel && (
+                <Fragment>
+                  <div class="wizard-section-title">Signal</div>
+                  {create ? (
+                    <Fragment>
+                      <div class="wizard-field">
+                        <label>Name</label>
+                        <input class="prop-input" type="text" value={newName}
+                          placeholder="my_signal"
+                          onInput={(e) => setNewName((e.target as HTMLInputElement).value)} />
+                      </div>
+                      <div class="wizard-field">
+                        <label>Visibility</label>
+                        <select class="prop-input" value={visibility}
+                          onChange={(e) => setVisibility((e.target as HTMLSelectElement).value as any)}>
+                          {panelId && <option value="panel">This panel only</option>}
+                          <option value="user">My signals</option>
+                          <option value="global">Global (all users)</option>
+                        </select>
+                      </div>
+                    </Fragment>
+                  ) : (
+                    <p class="hint">Editing <b>{name}</b>.</p>
+                  )}
+                  <div class="wizard-field">
+                    <label>Unit</label>
+                    <input class="prop-input" type="text" value={unit}
+                      onInput={(e) => setUnit((e.target as HTMLInputElement).value)} />
+                  </div>
+                  <div class="wizard-field">
+                    <label>Description</label>
+                    <input class="prop-input" type="text" value={desc}
+                      onInput={(e) => setDesc((e.target as HTMLInputElement).value)} />
+                  </div>
+                  <div class="wizard-field">
+                    <label>Display low</label>
+                    <input class="prop-input" type="number" value={dispLow}
+                      onInput={(e) => setDispLow((e.target as HTMLInputElement).value)} />
+                  </div>
+                  <div class="wizard-field">
+                    <label>Display high</label>
+                    <input class="prop-input" type="number" value={dispHigh}
+                      onInput={(e) => setDispHigh((e.target as HTMLInputElement).value)} />
+                  </div>
+                  <div class="flow-palette-hint hint">Select a node to edit it, or add one from the palette.</div>
+                </Fragment>
+              )}
 
               {sel?.kind === 'source' && (
                 <Fragment>
                   <div class="wizard-section-title">Input signal</div>
-                  <div class="wizard-field">
-                    <label>Data source</label>
-                    <SearchableSelect value={sel.ds ?? ''} options={dataSources}
-                      onSelect={(ds) => { loadSignals(ds); patchNode(sel.id, { ds, signal: '' }); }} />
-                  </div>
                   <div class="wizard-field">
                     <label>Signal</label>
-                    <SearchableSelect value={sel.signal ?? ''} options={dsSignals[sel.ds ?? ''] ?? []}
+                    <SignalPicker
-                      onSelect={(signal) => patchNode(sel.id, { signal })}
+                      value={sel.signal ? `${sel.ds ?? ''}:${sel.signal}` : ''}
-                      placeholder={sel.ds ? 'Search signals…' : 'Select data source first'} />
+                      options={allSignalOptions()}
+                      onOpen={openAllSignals}
+                      onChange={(ref) => {
+                        const i = ref.indexOf(':');
+                        if (i < 0) patchNode(sel.id, { ds: ref, signal: '' });
+                        else patchNode(sel.id, { ds: ref.slice(0, i), signal: ref.slice(i + 1) });
+                      }} />
                   </div>
                   <button class="panel-btn" style="margin-top:1rem;" onClick={() => deleteNode(sel.id)}>Delete node</button>
                 </Fragment>
@@ -538,8 +822,23 @@ export default function SyntheticGraphEditor({ name, onClose, onSaved }: Props)
               {sel?.kind === 'op' && (
                 <Fragment>
                   <div class="wizard-section-title">{opLabel(sel.op ?? '')}</div>
-                  {opParamDefs(sel.op ?? '').length === 0 && (
+                  {opArity(sel.op).kind === 'named' && (
-                    <p class="hint">No parameters — this operation transforms its input directly.</p>
+                    <div class="wizard-field">
+                      <label>Inputs</label>
+                      {((sel.params?.vars as string[] | undefined) ?? []).map((v, i) => (
+                        <div key={i} class="synth-var-row">
+                          <input class="prop-input" type="text" value={v}
+                            onInput={(e) => renameNamedVar(sel.id, i, (e.target as HTMLInputElement).value)} />
+                          <button class="icon-btn" title="Remove input"
+                            onClick={() => removeNamedVar(sel.id, i)}>✕</button>
+                        </div>
+                      ))}
+                      <button class="panel-btn" style="margin-top:0.4rem;" onClick={() => addNamedVar(sel.id)}>+ Input</button>
+                      <p class="hint" style="margin-top:0.4rem;">Use these names in the {sel.op === 'lua' ? 'script' : 'formula'} below.</p>
+                    </div>
+                  )}
+                  {opParamDefs(sel.op ?? '').length === 0 && opArity(sel.op).kind !== 'named' && (
+                    <p class="hint">No parameters — this operation transforms its inputs directly.</p>
                   )}
                   {opParamDefs(sel.op ?? '').map(pd => (
                     <div key={pd.key} class="wizard-field">
@@ -570,9 +869,9 @@ export default function SyntheticGraphEditor({ name, onClose, onSaved }: Props)
 
         <div class="wizard-footer">
           {error && <span class="wizard-error" style="flex:1;">{error}</span>}
-          {!error && compiled.error && <span class="hint" style="flex:1;">{compiled.error}</span>}
+          {!error && validationError && <span class="hint" style="flex:1;">{validationError}</span>}
           <button class="toolbar-btn" onClick={onClose}>Cancel</button>
-          <button class="toolbar-btn toolbar-btn-primary" onClick={handleSave} disabled={saving || loading || !!compiled.error}>
+          <button class="toolbar-btn toolbar-btn-primary" onClick={handleSave} disabled={saving || loading || !!validationError}>
             {saving ? 'Saving…' : 'Save Signal'}
           </button>
         </div>

web/src/SyntheticWizard.tsx

@@ -1,279 +0,0 @@
-import { h } from 'preact';
-import { useState, useEffect } from 'preact/hooks';
-import LuaEditor from './LuaEditor';
-import SearchableSelect from './SearchableSelect';
-import type { InputRef, SignalDef } from './lib/types';
-
-interface Props {
-  onClose: () => void;
-  onCreated: () => void;
-  // Interface id the wizard was opened from — used to bind panel-scoped signals.
-  currentIfaceId?: string;
-}
-
-interface NodeParam {
-  label: string;
-  key: string;
-  type: 'number' | 'text' | 'lua';
-  default: string;
-}
-
-const NODE_TYPES: Array<{ type: string; label: string; params: NodeParam[] }> = [
-  { type: 'gain',           label: 'Gain',            params: [{ label: 'Factor',           key: 'gain',   type: 'number', default: '1' }] },
-  { type: 'offset',         label: 'Offset',          params: [{ label: 'Offset',           key: 'offset', type: 'number', default: '0' }] },
-  { type: 'moving_average', label: 'Moving Average',  params: [{ label: 'Window (n)',       key: 'window', type: 'number', default: '10' }] },
-  { type: 'rms',            label: 'RMS',             params: [{ label: 'Window (n)',       key: 'window', type: 'number', default: '10' }] },
-  { type: 'lowpass',        label: 'Low-pass Filter', params: [
-    { label: 'Cutoff freq (Hz)', key: 'freq',  type: 'number', default: '1' },
-    { label: 'Order (1–8)',      key: 'order', type: 'number', default: '1' },
-  ]},
-  { type: 'derivative',     label: 'Derivative',      params: [] },
-  { type: 'integrate',      label: 'Integrate',       params: [] },
-  { type: 'clamp',          label: 'Clamp',           params: [{ label: 'Min', key: 'min', type: 'number', default: '0' }, { label: 'Max', key: 'max', type: 'number', default: '100' }] },
-  { type: 'expr',           label: 'Formula',         params: [{ label: 'Expression (a,b,c,d = inputs)', key: 'expr',   type: 'text', default: 'a * 1.0' }] },
-  { type: 'lua',            label: 'Lua Script',      params: [{ label: 'Script (a,b,c,d = inputs)',      key: 'script', type: 'lua',  default: 'return a' }] },
-];
-
-interface DataSource {
-  name: string;
-}
-
-interface SignalInfo {
-  name: string;
-  description?: string;
-}
-
-// ── Main Wizard ──────────────────────────────────────────────────────────────
-
-export default function SyntheticWizard({ onClose, onCreated, currentIfaceId }: Props) {
-  const [name, setName] = useState('');
-  const [inputs, setInputs] = useState<InputRef[]>([{ ds: 'stub', signal: 'sine_1hz' }]);
-  const [nodeType, setNodeType] = useState('gain');
-  const [params, setParams] = useState<Record<string, string>>({});
-  // Visibility scope. Panel scope requires an interface to bind to, so when the
-  // wizard is opened outside a saved panel it falls back to 'user'.
-  const [visibility, setVisibility] = useState<'panel' | 'user' | 'global'>(currentIfaceId ? 'panel' : 'user');
-  const [unit, setUnit] = useState('');
-  const [desc, setDesc] = useState('');
-  const [dispLow, setDispLow] = useState('0');
-  const [dispHigh, setDispHigh] = useState('100');
-  const [saving, setSaving] = useState(false);
-  const [error, setError] = useState('');
-
-  // Loaded data
-  const [dataSources, setDataSources] = useState<string[]>([]);
-  const [dsSignals, setDsSignals] = useState<Record<string, string[]>>({});
-
-  useEffect(() => {
-    fetch('/api/v1/datasources')
-      .then(r => r.ok ? r.json() : [])
-      .then((ds: DataSource[]) => setDataSources(ds.map(d => d.name)))
-      .catch(() => {});
-  }, []);
-
-  async function loadSignals(ds: string) {
-    if (dsSignals[ds]) return;
-    try {
-      const res = await fetch(`/api/v1/signals?ds=${encodeURIComponent(ds)}`);
-      if (!res.ok) return;
-      const sigs: SignalInfo[] = await res.json();
-      setDsSignals(prev => ({ ...prev, [ds]: sigs.map(s => s.name) }));
-    } catch {}
-  }
-
-  const nodeDef = NODE_TYPES.find(n => n.type === nodeType)!;
-
-  function getParam(key: string, def: string): string {
-    return params[key] ?? def;
-  }
-
-  function setParam(key: string, val: string) {
-    setParams(p => ({ ...p, [key]: val }));
-  }
-
-  function updateInput(idx: number, patch: Partial<InputRef>) {
-    setInputs(prev => prev.map((inp, i) => {
-      if (i !== idx) return inp;
-      const next = { ...inp, ...patch };
-      if (patch.ds) {
-        next.signal = '';
-        loadSignals(patch.ds);
-      }
-      return next;
-    }));
-  }
-
-  function addInput() {
-    setInputs(prev => [...prev, { ds: dataSources[0] || '', signal: '' }]);
-  }
-
-  function removeInput(idx: number) {
-    setInputs(prev => prev.filter((_, i) => i !== idx));
-  }
-
-  async function handleCreate() {
-    if (!name.trim()) { setError('Name is required'); return; }
-    if (inputs.some(i => !i.ds || !i.signal)) { setError('All inputs must have a data source and signal'); return; }
-
-    const nodeParams: Record<string, any> = {};
-    for (const p of nodeDef.params) {
-      const raw = getParam(p.key, p.default);
-      nodeParams[p.key] = p.type === 'number' ? parseFloat(raw) : raw;
-    }
-
-    const def: SignalDef = {
-      name: name.trim(),
-      inputs,
-      pipeline: [{ type: nodeType, params: nodeParams }],
-      meta: {
-        unit: unit || undefined,
-        description: desc || undefined,
-        displayLow: parseFloat(dispLow) || 0,
-        displayHigh: parseFloat(dispHigh) || 100,
-      },
-      visibility,
-      ...(visibility === 'panel' && currentIfaceId ? { panel: currentIfaceId } : {}),
-    };
-
-    setSaving(true);
-    setError('');
-    try {
-      const res = await fetch('/api/v1/synthetic', {
-        method: 'POST',
-        headers: { 'Content-Type': 'application/json' },
-        body: JSON.stringify(def),
-      });
-      if (!res.ok) {
-        const j = await res.json().catch(() => ({ error: res.statusText }));
-        throw new Error(j.error ?? res.statusText);
-      }
-      onCreated();
-      onClose();
-    } catch (err) {
-      setError(err instanceof Error ? err.message : String(err));
-    } finally {
-      setSaving(false);
-    }
-  }
-
-  return (
-    <div class="wizard-backdrop" onClick={onClose}>
-      <div class="wizard" onClick={(e) => e.stopPropagation()}>
-        <div class="wizard-header">
-          <span>New Synthetic Signal</span>
-          <button class="icon-btn" onClick={onClose}>✕</button>
-        </div>
-
-        <div class="wizard-body">
-          {error && <p class="wizard-error">{error}</p>}
-
-          <div class="wizard-section-title">Signal identity</div>
-          <div class="wizard-field">
-            <label>Name</label>
-            <input class="prop-input" value={name}
-              placeholder="e.g. smoothed_pressure"
-              onInput={(e) => setName((e.target as HTMLInputElement).value)} />
-          </div>
-
-          <div class="wizard-field">
-            <label>Visibility</label>
-            <select class="prop-select" value={visibility}
-              onChange={(e) => setVisibility((e.target as HTMLSelectElement).value as any)}>
-              <option value="panel" disabled={!currentIfaceId}>
-                This panel only{currentIfaceId ? '' : ' (save panel first)'}
-              </option>
-              <option value="user">All my panels</option>
-              <option value="global">All panels (global)</option>
-            </select>
-          </div>
-
-          <div class="wizard-section-title">Input signals</div>
-          {inputs.map((inp, idx) => (
-            <div key={idx} class="wizard-field wizard-field-row" style="align-items: flex-end; gap: 0.5rem; margin-bottom: 0.5rem;">
-              <div class="wizard-field" style="flex:1;">
-                <label>Data source</label>
-                <SearchableSelect
-                  value={inp.ds}
-                  options={dataSources}
-                  onSelect={(ds) => updateInput(idx, { ds })}
-                />
-              </div>
-              <div class="wizard-field" style="flex:2;">
-                <label>Signal</label>
-                <SearchableSelect
-                  value={inp.signal}
-                  options={dsSignals[inp.ds] || []}
-                  onSelect={(signal) => updateInput(idx, { signal })}
-                  placeholder={inp.ds ? 'Search signals…' : 'Select data source first'}
-                />
-              </div>
-              <button
-                class="icon-btn"
-                style="margin-bottom: 0.25rem;"
-                title="Remove input"
-                onClick={() => removeInput(idx)}
-                disabled={inputs.length === 1}
-              >✕</button>
-            </div>
-          ))}
-          <button class="panel-btn" style="margin-top: 0.5rem;" onClick={addInput}>+ Add input</button>
-
-          <div class="wizard-section-title" style="margin-top: 1.5rem;">Processing</div>
-          <div class="wizard-field">
-            <label>Node type</label>
-            <select class="prop-select" value={nodeType}
-              onChange={(e) => { setNodeType((e.target as HTMLSelectElement).value); setParams({}); }}>
-              {NODE_TYPES.map(n => <option key={n.type} value={n.type}>{n.label}</option>)}
-            </select>
-          </div>
-          {nodeDef.params.map(p => (
-            <div key={p.key} class="wizard-field">
-              <label>{p.label}</label>
-              {p.type === 'lua' ? (
-                <LuaEditor
-                  value={getParam(p.key, p.default)}
-                  onChange={(v) => setParam(p.key, v)}
-                />
-              ) : (
-                <input class="prop-input" type={p.type === 'number' ? 'number' : 'text'}
-                  value={getParam(p.key, p.default)}
-                  onInput={(e) => setParam(p.key, (e.target as HTMLInputElement).value)} />
-              )}
-            </div>
-          ))}
-
-          <div class="wizard-section-title">Metadata (optional)</div>
-          <div class="wizard-field wizard-field-row">
-            <div class="wizard-field">
-              <label>Unit</label>
-              <input class="prop-input" value={unit} placeholder="m/s"
-                onInput={(e) => setUnit((e.target as HTMLInputElement).value)} />
-            </div>
-            <div class="wizard-field">
-              <label>Display low</label>
-              <input class="prop-input" type="number" value={dispLow}
-                onInput={(e) => setDispLow((e.target as HTMLInputElement).value)} />
-            </div>
-            <div class="wizard-field">
-              <label>Display high</label>
-              <input class="prop-input" type="number" value={dispHigh}
-                onInput={(e) => setDispHigh((e.target as HTMLInputElement).value)} />
-            </div>
-          </div>
-          <div class="wizard-field">
-            <label>Description</label>
-            <input class="prop-input" value={desc} placeholder="Optional description"
-              onInput={(e) => setDesc((e.target as HTMLInputElement).value)} />
-          </div>
-        </div>
-
-        <div class="wizard-footer">
-          <button class="toolbar-btn" onClick={onClose}>Cancel</button>
-          <button class="toolbar-btn toolbar-btn-primary" onClick={handleCreate} disabled={saving}>
-            {saving ? 'Creating…' : 'Create Signal'}
-          </button>
-        </div>
-      </div>
-    </div>
-  );
-}

web/src/ViewMode.tsx

@@ -7,10 +7,10 @@ import { parseInterface } from './lib/xml';
 import { newPlotPanel } from './lib/templates';
 import { useAuth, canWrite } from './lib/auth';
 import type { Interface } from './lib/types';
-import ContextualHelp from './ContextualHelp';
 import HelpModal from './HelpModal';
 import ZoomControl from './ZoomControl';
 import ControlLogicEditor from './ControlLogicEditor';
+import AuditViewer from './AuditViewer';
 
 interface Props {
   onEdit?: (iface?: Interface) => void;
@@ -33,6 +33,7 @@ export default function ViewMode({ onEdit, initialInterface, onView }: Props) {
   const [helpSection, setHelpSection] = useState('start');
   const [showTimeNav, setShowTimeNav] = useState(false);
   const [showControlLogic, setShowControlLogic] = useState(false);
+  const [showAudit, setShowAudit] = useState(false);
   const [leftW, setLeftW] = useState(220);
   const [listCollapsed, setListCollapsed] = useState(false);
   const me = useAuth();
@@ -137,9 +138,13 @@ export default function ViewMode({ onEdit, initialInterface, onView }: Props) {
           )}
         </div>
         <div class="toolbar-right">
-          <div class={`status-chip ${wsStatus}`}>
+          <div
+            class={`status-chip ${wsStatus}`}
+            title={me.user ? `Signed in as ${me.user}${writable ? '' : ' (read-only)'}` : undefined}
+          >
             <span class="status-dot"></span>
             {wsStatus === 'connected' && me.user ? `connected as ${me.user}` : wsStatus}
+            {me.user && !writable && ' (read-only)'}
           </div>
           <button
             class={`toolbar-btn${showTimeNav ? ' toolbar-btn-active' : ''}`}
@@ -148,7 +153,6 @@ export default function ViewMode({ onEdit, initialInterface, onView }: Props) {
           >
             ⏱ History
           </button>
-          <ContextualHelp mode="view" onOpenManual={openHelp} />
           <button
             class="icon-btn help-manual-btn"
             onClick={() => openHelp('start')}
@@ -166,6 +170,15 @@ export default function ViewMode({ onEdit, initialInterface, onView }: Props) {
               ⚙ Control logic
             </button>
           )}
+          {me.canViewAudit && (
+            <button
+              class="toolbar-btn"
+              onClick={() => setShowAudit(true)}
+              title="View the audit log"
+            >
+              🛡 Audit
+            </button>
+          )}
           {writable && (
             <button
               class="btn-edit"
@@ -175,11 +188,6 @@ export default function ViewMode({ onEdit, initialInterface, onView }: Props) {
               Edit
             </button>
           )}
-          {me.user && (
-            <span class="user-chip" title={`Signed in as ${me.user}${writable ? '' : ' (read-only)'}`}>
-              {me.user}{!writable && ' (read-only)'}
-            </span>
-          )}
         </div>
       </header>
 
@@ -257,6 +265,10 @@ export default function ViewMode({ onEdit, initialInterface, onView }: Props) {
       {showControlLogic && (
         <ControlLogicEditor onClose={() => setShowControlLogic(false)} />
       )}
+
+      {showAudit && (
+        <AuditViewer onClose={() => setShowAudit(false)} />
+      )}
     </div>
   );
 }

web/src/lib/auth.ts

@@ -4,7 +4,7 @@ import type { Me, AccessLevel } from './types';
 
 // Default identity used before /api/v1/me resolves (or if it fails): assume a
 // trusted LAN user with full access, matching the backend default.
-export const DEFAULT_ME: Me = { user: '', level: 'write', groups: [], canEditLogic: true };
+export const DEFAULT_ME: Me = { user: '', level: 'write', groups: [], canEditLogic: true, canViewAudit: true };
 
 // AuthContext carries the resolved identity + global access level for the
 // current user throughout the app.
@@ -37,6 +37,7 @@ export async function fetchMe(): Promise<Me> {
       level: (data.level as AccessLevel) ?? 'write',
       groups: Array.isArray(data.groups) ? data.groups : [],
       canEditLogic: data.canEditLogic !== false,
+      canViewAudit: data.canViewAudit !== false,
     };
   } catch {
     return DEFAULT_ME;

web/src/lib/controldialogs.ts

@@ -0,0 +1,24 @@
+import { writable } from './store';
+
+// A dialog request pushed by a server-side control-logic action.dialog node and
+// delivered over the WebSocket. Unlike panel logic dialogs (lib/logic.ts) these
+// originate on the server and are addressed to the connected user by identity.
+export interface ControlDialog {
+  id: string;
+  kind: 'info' | 'error' | 'input';
+  title?: string;
+  message?: string;
+}
+
+// Active control-logic dialogs awaiting the user's acknowledgement / input.
+export const controlDialogs = writable<ControlDialog[]>([]);
+
+// pushControlDialog is invoked by the WS client on a "dialog" message.
+export function pushControlDialog(d: ControlDialog): void {
+  controlDialogs.update(list => (list.some(x => x.id === d.id) ? list : [...list, d]));
+}
+
+// dismissControlDialog removes a dialog once answered or cancelled.
+export function dismissControlDialog(id: string): void {
+  controlDialogs.update(list => list.filter(d => d.id !== id));
+}

web/src/lib/types.ts

@@ -9,6 +9,9 @@ export interface SignalValue {
   value: any;
   quality: 'good' | 'uncertain' | 'bad' | 'unknown';
   ts: string | null;
+  // Raw EPICS alarm fields (absent/0 = NO_ALARM). severity: 1=MINOR,2=MAJOR,3=INVALID.
+  severity?: number;
+  status?: number;
 }
 
 // Metadata for a signal (received once on subscribe)
@@ -209,6 +212,9 @@ export interface Me {
   // Whether the user may add/edit panel logic and server-side control logic.
   // False only when a logic-editors allowlist is configured and excludes them.
   canEditLogic: boolean;
+  // Whether the user may view the audit log. False only when an audit-readers
+  // allowlist is configured and excludes them, or auditing is disabled.
+  canViewAudit: boolean;
 }
 
 // Effective permission a user holds on a single panel or folder.
@@ -269,12 +275,33 @@ export interface PipelineNode {
   params: Record<string, any>;
 }
 
+// DAG form of a synthetic signal (mirrors backend synthetic.Graph). A node is a
+// source (ds:signal root), an op (DSP node with ordered `inputs`), or the single
+// output. When present it supersedes the legacy inputs+pipeline linear form.
+export type SynthNodeKind = 'source' | 'op' | 'output';
+export interface SynthGraphNode {
+  id: string;
+  kind: SynthNodeKind;
+  op?: string;
+  params?: Record<string, any>;
+  ds?: string;
+  signal?: string;
+  inputs?: string[]; // upstream node ids, in input order
+  x?: number;
+  y?: number;
+}
+export interface SynthGraph {
+  nodes: SynthGraphNode[];
+  output: string;
+}
+
 export interface SignalDef {
   name: string;
   ds?: string;      // legacy single input
   signal?: string;  // legacy single input
   inputs?: InputRef[];
-  pipeline: PipelineNode[];
+  pipeline?: PipelineNode[];
+  graph?: SynthGraph; // DAG form (preferred when present)
   meta: {
     unit?: string;
     description?: string;

web/src/lib/ws.ts

@@ -1,5 +1,6 @@
 import { writable, type Readable } from './store';
 import { writeLocalState } from './localstate';
+import { pushControlDialog } from './controldialogs';
 import type { SignalRef, SignalValue, SignalMeta, HistoryPoint } from './types';
 
 // ── Types ────────────────────────────────────────────────────────────────────
@@ -130,6 +131,8 @@ class WsClient {
           value: msg.value,
           quality: msg.quality ?? 'unknown',
           ts: msg.ts ?? null,
+          severity: msg.severity ?? 0,
+          status: msg.status ?? 0,
         };
         for (const s of subs) s.onUpdate(val);
         break;
@@ -161,6 +164,16 @@ class WsClient {
         }
         break;
       }
+      case 'dialog': {
+        // Server-side control logic requesting a user notification / input.
+        pushControlDialog({
+          id: String(msg.id),
+          kind: msg.kind === 'error' || msg.kind === 'input' ? msg.kind : 'info',
+          title: msg.title,
+          message: msg.message,
+        });
+        break;
+      }
       case 'error':
         // Resolve any pending history callbacks with empty data on error
         if (key && this.histCallbacks.has(key)) {
@@ -268,6 +281,14 @@ class WsClient {
     console.log('[ws] write', ref.ds, ref.name, value, 'ws state:', this.ws?.readyState);
     this._send({ type: 'write', ds: ref.ds, name: ref.name, value });
   }
+
+  /**
+   * Answer a control-logic input dialog. `value === null` cancels (dismisses)
+   * the dialog without writing its target server variable.
+   */
+  sendDialogResponse(id: string, value: number | null): void {
+    this._send({ type: 'dialogResponse', id, value });
+  }
 }
 
 // Singleton instance

web/src/styles.css

@@ -123,6 +123,8 @@ body {
   color: #94a3b8;
   border: 1px solid #334155;
   text-transform: capitalize;
+  white-space: nowrap;
+  flex-shrink: 0;
 }
 
 .status-chip.connected {
@@ -165,18 +167,6 @@ body {
 }
 
 /* ── User identity chip ──────────────────────────────────────────────────── */
-.user-chip {
-  display: flex;
-  align-items: center;
-  font-size: 0.75rem;
-  padding: 0.2rem 0.6rem;
-  border-radius: 9999px;
-  background: #1e293b;
-  color: #cbd5e1;
-  border: 1px solid #334155;
-  white-space: nowrap;
-}
-
 /* ── Access denied screen ────────────────────────────────────────────────── */
 .access-denied {
   display: flex;
@@ -1273,6 +1263,8 @@ body {
 .flow-node-flow    { border-top: 3px solid #10b981; }
 .flow-node-action  { border-top: 3px solid #3b82f6; }
 .flow-node-selected { border-color: #3b82f6; box-shadow: 0 0 0 2px #3b82f680; }
+.flow-node-error { border-color: #ef4444; box-shadow: 0 0 0 2px #ef444455; }
+.flow-node-error.flow-node-selected { box-shadow: 0 0 0 2px #ef4444aa; }
 
 .flow-node-header {
   display: flex;
@@ -1319,6 +1311,24 @@ body {
   pointer-events: none;
 }
 
+/* Named input ports (Formula/Lua) show their variable name beside the port. */
+.flow-port-label-in {
+  position: absolute;
+  left: 0.55rem;
+  font-size: 0.6rem;
+  color: #94a3b8;
+  pointer-events: none;
+}
+
+/* Named-input editor row in the inspector */
+.synth-var-row {
+  display: flex;
+  gap: 0.35rem;
+  align-items: center;
+  margin-bottom: 0.3rem;
+}
+.synth-var-row > input { flex: 1; min-width: 0; }
+
 /* Expression field: signal-insert helper row */
 .flow-expr-insert {
   display: flex;
@@ -2746,90 +2756,50 @@ kbd {
   color: #e2e8f0;
 }
 
-/* ── Contextual Help ─────────────────────────────────────────────────────── */
+/* ── Manual: Quick Tips list ─────────────────────────────────────────────── */
 
-.ctx-help {
+.help-tips-list {
-  position: relative;
+  list-style: none;
-  display: flex;
+  margin: 0 0 1rem;
-  align-items: center;
-}
-
-.ctx-help-btn {
-  width: 22px;
-  height: 22px;
-  border-radius: 50%;
-  border: 1.5px solid #4a5568;
-  background: #1a2236;
-  color: #94a3b8;
-  font-size: 0.78rem;
-  font-weight: 700;
-  cursor: pointer;
-  display: flex;
-  align-items: center;
-  justify-content: center;
-  transition: border-color 0.15s, color 0.15s;
-  flex-shrink: 0;
-  line-height: 1;
   padding: 0;
+  display: flex;
+  flex-direction: column;
+  gap: 0.4rem;
 }
-.ctx-help-btn:hover { border-color: #4a9eff; color: #4a9eff; }
 
-.ctx-help-popover {
+.help-tip-item {
-  position: absolute;
+  display: flex;
-  top: calc(100% + 8px);
+  align-items: center;
-  right: 0;
+  gap: 0.6rem;
-  z-index: 400;
+  width: 100%;
+  text-align: left;
   background: #1a1f2e;
   border: 1px solid #2d3748;
-  border-radius: 8px;
+  border-radius: 6px;
-  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.5);
+  padding: 0.55rem 0.7rem;
-  width: 280px;
-  padding: 0.75rem;
-}
-
-.ctx-help-tip {
-  display: flex;
-  gap: 0.5rem;
-  font-size: 0.82rem;
   color: #cbd5e1;
-  line-height: 1.5;
+  font-size: 0.85rem;
-  margin-bottom: 0.6rem;
+  line-height: 1.45;
+  cursor: pointer;
+  transition: border-color 0.15s, background 0.15s;
+}
+.help-tip-item:hover {
+  border-color: #4a9eff;
+  background: #1e2540;
 }
 
-.ctx-help-icon {
+.help-tip-icon {
-  font-size: 1rem;
   flex-shrink: 0;
-  margin-top: 0.05rem;
+  font-size: 1rem;
 }
 
-.ctx-help-footer {
+.help-tip-text { flex: 1; }
-  display: flex;
-  justify-content: space-between;
-  align-items: center;
-  border-top: 1px solid #2d3748;
-  padding-top: 0.5rem;
-  gap: 0.5rem;
-}
 
-.ctx-help-nav {
+.help-tip-go {
-  font-size: 0.75rem;
+  flex-shrink: 0;
-  color: #64748b;
-  background: none;
-  border: none;
-  cursor: pointer;
-  padding: 0;
-}
-.ctx-help-nav:hover { color: #94a3b8; }
-
-.ctx-help-link {
-  font-size: 0.75rem;
   color: #4a9eff;
-  background: none;
+  font-weight: 700;
-  border: none;
-  cursor: pointer;
-  padding: 0;
 }
-.ctx-help-link:hover { text-decoration: underline; }
 
 
 /* ── Historical time-nav bar (below main toolbar, hidden by default) ──────── */
@@ -3446,6 +3416,37 @@ kbd {
   overflow: hidden;
 }
 
+.cl-confirm-overlay {
+  position: fixed;
+  inset: 0;
+  background: rgba(0, 0, 0, 0.55);
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  z-index: 650;
+}
+
+.cl-confirm {
+  background: #1a1f2e;
+  border: 1px solid #2d3748;
+  border-radius: 10px;
+  padding: 1.25rem 1.5rem;
+  width: min(440px, 92vw);
+  box-shadow: 0 16px 48px rgba(0, 0, 0, 0.6);
+}
+
+.cl-confirm-title {
+  font-weight: 600;
+  margin-bottom: 0.5rem;
+}
+
+.cl-confirm-actions {
+  display: flex;
+  justify-content: flex-end;
+  gap: 0.5rem;
+  margin-top: 1.25rem;
+}
+
 .cl-header {
   display: flex;
   align-items: center;
@@ -3455,6 +3456,127 @@ kbd {
   flex-shrink: 0;
 }
 
+/* ── Audit log viewer ──────────────────────────────────────────────────── */
+.audit-modal {
+  width: min(1300px, 98vw);
+}
+
+.audit-filters {
+  display: flex;
+  align-items: center;
+  flex-wrap: wrap;
+  gap: 0.5rem;
+  padding: 0.6rem 1.25rem;
+  border-bottom: 1px solid #2d3748;
+  flex-shrink: 0;
+}
+
+.audit-filter {
+  background: #0f1420;
+  border: 1px solid #2d3748;
+  border-radius: 5px;
+  color: #e2e8f0;
+  padding: 0.3rem 0.5rem;
+  font-size: 0.8rem;
+}
+
+.audit-filter-label {
+  display: flex;
+  align-items: center;
+  gap: 0.3rem;
+  font-size: 0.75rem;
+  color: #94a3b8;
+}
+
+.audit-body {
+  flex: 1;
+  overflow: auto;
+  padding: 0 0 0.5rem;
+}
+
+.audit-empty {
+  padding: 1.5rem 1.25rem;
+}
+
+.audit-table {
+  width: 100%;
+  border-collapse: collapse;
+  font-size: 0.8rem;
+}
+
+.audit-table th,
+.audit-table td {
+  text-align: left;
+  padding: 0.35rem 0.6rem;
+  border-bottom: 1px solid #232b3a;
+  white-space: nowrap;
+}
+
+.audit-table th {
+  position: sticky;
+  top: 0;
+  background: #161c2a;
+  color: #94a3b8;
+  font-weight: 600;
+  z-index: 1;
+}
+
+.audit-table tbody tr:hover {
+  background: #1d2433;
+}
+
+.audit-row-error td {
+  background: rgba(220, 38, 38, 0.08);
+}
+
+.audit-time {
+  color: #94a3b8;
+  font-variant-numeric: tabular-nums;
+}
+
+.audit-signal,
+.audit-detail {
+  max-width: 18rem;
+  overflow: hidden;
+  text-overflow: ellipsis;
+}
+
+.audit-value {
+  max-width: 10rem;
+  overflow: hidden;
+  text-overflow: ellipsis;
+  font-family: ui-monospace, monospace;
+}
+
+.audit-actor-tag {
+  display: inline-block;
+  font-size: 0.65rem;
+  text-transform: uppercase;
+  letter-spacing: 0.03em;
+  padding: 0.05rem 0.35rem;
+  border-radius: 3px;
+  vertical-align: middle;
+}
+
+.audit-actor-user {
+  background: #1e3a5f;
+  color: #93c5fd;
+}
+
+.audit-actor-system {
+  background: #4a2d6b;
+  color: #d8b4fe;
+}
+
+.audit-result-ok {
+  color: #4ade80;
+}
+
+.audit-result-err {
+  color: #f87171;
+  font-weight: 600;
+}
+
 .cl-title {
   font-size: 1rem;
   font-weight: 700;

web/src/widgets/PlotWidget.tsx

@@ -90,6 +90,17 @@ export default function PlotWidget({ widget, onContextMenu, timeRange }: Props)
     // ── uPlot (timeseries) ──────────────────────────────────────────────────
     let uplot: uPlot | null = null;
 
+    // Newest sample timestamp across all series (seconds). Anchoring the live
+    // x-axis to this — rather than wall-clock Date.now() — avoids client/server
+    // clock skew clipping the latest point, and keeps the right edge on real data.
+    function latestSampleTs(): number {
+      let m = -Infinity;
+      for (const b of buffers) {
+        if (b.timestamps.length) m = Math.max(m, b.timestamps[b.timestamps.length - 1]);
+      }
+      return isFinite(m) ? m : Date.now() / 1000;
+    }
+
     // windowSec: apply rolling window for live mode; 0 = use full buffer (historical)
     function uplotData(windowSec = 0): uPlot.AlignedData {
       if (signals.length === 0) return [[]];
@@ -165,7 +176,22 @@ export default function PlotWidget({ widget, onContextMenu, timeRange }: Props)
           { stroke: '#94a3b8', grid: { stroke: '#2d3748' }, ticks: { stroke: '#475569' } },
           yAxis,
         ],
-        scales: { x: { time: true }, y: { ...scaleY, range: scaleYRange } },
+        scales: {
+          x: {
+            time: true,
+            // Live mode with a finite window: pin the x-axis to a rolling
+            // [newest − window, newest] span so a single old/outlier sample
+            // can't stretch the axis and compress real points to the right.
+            // Historical mode (timeRange) keeps uPlot's data-driven auto-range.
+            ...(!timeRange && timeWindow > 0
+              ? { range: (): [number, number] => {
+                  const r = latestSampleTs();
+                  return [r - timeWindow, r];
+                } }
+              : {}),
+          },
+          y: { ...scaleY, range: scaleYRange },
+        },
       };
     }
 

workspace/data/acl.json

@@ -1,10 +1,31 @@
 {
-  "panels": {},
+  "panels": {
+    "epics_test": {
+      "owner": ""
+    },
+    "new-plot-panel": {
+      "owner": "",
+      "folder": "fld-c5396468072d4f69"
+    },
+    "test": {
+      "owner": "martino",
+      "order": 1
+    },
+    "test-1781729251317": {
+      "owner": "",
+      "order": 3
+    }
+  },
   "folders": {
     "fld-68b0bb9c23c9fd3b": {
       "id": "fld-68b0bb9c23c9fd3b",
       "name": "Test",
       "owner": ""
+    },
+    "fld-c5396468072d4f69": {
+      "id": "fld-c5396468072d4f69",
+      "name": "Plots",
+      "owner": "martino"
     }
   }
 }

workspace/data/controllogic.json

@@ -0,0 +1 @@
+[]

workspace/data/trash/controllogic/cl-0f99598ca4d0ea15.1781883404740.json

@@ -0,0 +1,7 @@
+{
+  "id": "cl-0f99598ca4d0ea15",
+  "name": "New control logic",
+  "enabled": false,
+  "nodes": [],
+  "wires": []
+}