feat(companion): add clearEventSubscriptions helper

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()`).
+- `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/platformClients.ts` provides platform-focused wrappers:
   - `MacOSCompanionClient` (`platform: "macos"`, APNs push registration)
   - `IOSCompanionClient` (`platform: "ios"`, APNs push registration)

docs/plans/state.json

@@ -395,6 +395,19 @@
       ],
       "test_status": "pnpm test:run src/companion/platformClients.test.ts src/companion/heartbeatLoop.test.ts src/companion/runtimeClient.test.ts src/companion/platformClients.integration.test.ts + pnpm typecheck passing"
     },
+    "companion-runtime-clear-event-subscriptions": {
+      "status": "completed",
+      "date": "2026-02-17",
+      "updated": "2026-02-17",
+      "summary": "Added `clearEventSubscriptions()` to `CompanionRuntimeClient` for explicit teardown of all registered event handlers, with test coverage for generic + filtered subscriptions.",
+      "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/platformClients.test.ts src/companion/platformClients.integration.test.ts src/companion/heartbeatLoop.test.ts + pnpm typecheck passing"
+    },
     "browser-tools-activation-clarity": {
       "status": "completed",
       "date": "2026-02-17",

src/companion/runtimeClient.test.ts

@@ -196,6 +196,28 @@ describe('CompanionRuntimeClient', () => {
     expect(streamHandler).toHaveBeenCalledTimes(1);
   });
 
+  it('clears all event subscriptions', () => {
+    const client = new CompanionRuntimeClient({
+      url: 'ws://127.0.0.1:1',
+    });
+    const handlerA = vi.fn();
+    const handlerB = vi.fn();
+    client.subscribeEvents(handlerA);
+    client.subscribeEvent('agent.stream', handlerB);
+    client.clearEventSubscriptions();
+
+    (client as unknown as { handleMessage: (raw: string) => void }).handleMessage(
+      JSON.stringify({
+        id: 50,
+        event: 'agent.stream',
+        data: { token: 'cleared' },
+      }),
+    );
+
+    expect(handlerA).not.toHaveBeenCalled();
+    expect(handlerB).not.toHaveBeenCalled();
+  });
+
   it('waitForEvent resolves using optional predicate filter', async () => {
     const client = new CompanionRuntimeClient({
       url: 'ws://127.0.0.1:1',

src/companion/runtimeClient.ts

@@ -364,6 +364,10 @@ export class CompanionRuntimeClient {
     };
   }
 
+  clearEventSubscriptions(): void {
+    this.eventHandlers.clear();
+  }
+
   subscribeEvent<TData = unknown>(
     eventName: string,
     handler: CompanionTypedEventHandler<TData>,