feat(companion): add AbortSignal support for waitForEvent

README.md

@@ -1190,7 +1190,7 @@ Methods:
 - `system.capabilities` returns gateway protocol and node policy snapshot.
 
 Companion runtime helper:
-- `src/companion/runtimeClient.ts` provides a typed Node/WebSocket client for companion runtimes (macOS/iOS/Android workers) with wrappers for `node.register`, `node.capabilities.get`, `node.location.set/get`, `node.status.set`, `node.push_token.set`, `system.capabilities`, `system.nodes`, and canvas artifact RPCs (`canvas.put/get/list/delete/clear`), plus convenience helpers (`bootstrapNode`, optional `autoConnect`) and event helpers (`subscribeEvents()`, `subscribeEvent()`, `waitForEvent()`, `clearEventSubscriptions()`).
+- `src/companion/runtimeClient.ts` provides a typed Node/WebSocket client for companion runtimes (macOS/iOS/Android workers) with wrappers for `node.register`, `node.capabilities.get`, `node.location.set/get`, `node.status.set`, `node.push_token.set`, `system.capabilities`, `system.nodes`, and canvas artifact RPCs (`canvas.put/get/list/delete/clear`), plus convenience helpers (`bootstrapNode`, optional `autoConnect`) and event helpers (`subscribeEvents()`, `subscribeEvent()`, `waitForEvent()` with timeout/predicate/abort support, `clearEventSubscriptions()`).
 - `src/companion/platformClients.ts` provides platform-focused wrappers:
   - `MacOSCompanionClient` (`platform: "macos"`, APNs push registration)
   - `IOSCompanionClient` (`platform: "ios"`, APNs push registration)

docs/plans/state.json

@@ -421,6 +421,19 @@
       ],
       "test_status": "pnpm test:run src/companion/heartbeatLoop.test.ts src/companion/runtimeClient.test.ts src/companion/platformClients.test.ts src/companion/platformClients.integration.test.ts + pnpm typecheck passing"
     },
+    "companion-runtime-wait-for-event-abort-signal": {
+      "status": "completed",
+      "date": "2026-02-17",
+      "updated": "2026-02-17",
+      "summary": "Extended `waitForEvent()` with `AbortSignal` support so companion runtimes can cancel pending event waits deterministically (in addition to timeout-based cancellation).",
+      "files_modified": [
+        "src/companion/runtimeClient.ts",
+        "src/companion/runtimeClient.test.ts",
+        "README.md",
+        "docs/plans/state.json"
+      ],
+      "test_status": "pnpm test:run src/companion/runtimeClient.test.ts src/companion/heartbeatLoop.test.ts src/companion/platformClients.test.ts src/companion/platformClients.integration.test.ts + pnpm typecheck passing"
+    },
     "browser-tools-activation-clarity": {
       "status": "completed",
       "date": "2026-02-17",

src/companion/runtimeClient.test.ts

@@ -260,6 +260,19 @@ describe('CompanionRuntimeClient', () => {
     vi.useRealTimers();
   });
 
+  it('waitForEvent supports AbortSignal cancellation', async () => {
+    const client = new CompanionRuntimeClient({
+      url: 'ws://127.0.0.1:1',
+    });
+    const controller = new AbortController();
+
+    const awaited = expect(
+      client.waitForEvent('agent.stream', { signal: controller.signal, timeoutMs: 10_000 }),
+    ).rejects.toThrow('Aborted while waiting for event agent.stream');
+    controller.abort();
+    await awaited;
+  });
+
   it('connects and performs node registration + capability discovery', async () => {
     if (!LISTEN_ALLOWED) {
       return;

src/companion/runtimeClient.ts

@@ -385,34 +385,54 @@ export class CompanionRuntimeClient {
     options?: {
       timeoutMs?: number;
       predicate?: CompanionEventPredicate<TData>;
+      signal?: AbortSignal;
     },
   ): Promise<TData> {
     const timeoutMs = options?.timeoutMs ?? this.requestTimeoutMs;
     const predicate = options?.predicate;
+    const signal = options?.signal;
 
     return new Promise<TData>((resolve, reject) => {
       let settled = false;
-      const unsubscribe = this.subscribeEvent<TData>(eventName, (data) => {
-        if (predicate && !predicate(data)) {
-          return;
-        }
+      let abortCleanup: (() => void) | null = null;
+
+      const finish = (fn: () => void) => {
         if (settled) {
           return;
         }
         settled = true;
         clearTimeout(timeout);
         unsubscribe();
-        resolve(data);
+        if (abortCleanup) {
+          abortCleanup();
+          abortCleanup = null;
+        }
+        fn();
+      };
+
+      const unsubscribe = this.subscribeEvent<TData>(eventName, (data) => {
+        if (predicate && !predicate(data)) {
+          return;
+        }
+        finish(() => resolve(data));
       });
 
       const timeout = setTimeout(() => {
-        if (settled) {
-          return;
-        }
-        settled = true;
-        unsubscribe();
-        reject(new Error(`Timed out waiting for event ${eventName}`));
+        finish(() => reject(new Error(`Timed out waiting for event ${eventName}`)));
       }, timeoutMs);
+
+      if (signal) {
+        const onAbort = () => {
+          finish(() => reject(new Error(`Aborted while waiting for event ${eventName}`)));
+        };
+        signal.addEventListener('abort', onAbort, { once: true });
+        abortCleanup = () => {
+          signal.removeEventListener('abort', onAbort);
+        };
+        if (signal.aborted) {
+          onAbort();
+        }
+      }
     });
   }