diff --git a/web/src/lib/types.ts b/web/src/lib/types.ts
index dee3ab8..96a9f5b 100644
--- a/web/src/lib/types.ts
+++ b/web/src/lib/types.ts
@@ -68,11 +68,15 @@ export type PlotLayout =
 // via ds 'local'.
 export interface StateVar {
   name: string;
-  type?: 'number' | 'bool' | 'string'; // default 'number'
+  type?: 'number' | 'bool' | 'string' | 'array'; // default 'number'
   initial: string;                     // initial value, stored as a string
   unit?: string;
   low?: number;
   high?: number;
+  // array-only (present when type === 'array'):
+  elem?: 'number' | 'bool' | 'array';
+  sizing?: 'dynamic' | 'capped' | 'fixed';
+  capacity?: number;
 }
 
 // ── Panel logic (Node-RED–style flow graph) ──────────────────────────────────