feat(companion): expose pending event wait observability

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`, `dispose()`) and event helpers (`subscribeEvents()`, `subscribeEvent()`, `subscribeAgentStream()`, `subscribeAgentTyping()`, `subscribeContextWarning()`, `waitForEvent()` with timeout/predicate/abort support, non-empty event-name validation, and deterministic teardown cancellation (including socket-close rejection), `waitForAnyEvent()` (with non-empty event-name-list validation), `waitForAgentStream()`, `waitForAgentTyping()`, `waitForContextWarning()`, `clearEventSubscriptions()`, `listKnownEventNames()`, `eventSubscriptionCount`) plus in-flight RPC observability via `pendingRequestCount`.
+- `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`, `dispose()`) and event helpers (`subscribeEvents()`, `subscribeEvent()`, `subscribeAgentStream()`, `subscribeAgentTyping()`, `subscribeContextWarning()`, `waitForEvent()` with timeout/predicate/abort support, non-empty event-name validation, and deterministic teardown cancellation (including socket-close rejection), `waitForAnyEvent()` (with non-empty event-name-list validation), `waitForAgentStream()`, `waitForAgentTyping()`, `waitForContextWarning()`, `clearEventSubscriptions()`, `listKnownEventNames()`, `eventSubscriptionCount`) plus in-flight observability via `pendingRequestCount` and `pendingEventWaitCount`.
 - `src/companion/platformClients.ts` provides platform-focused wrappers:
   - `MacOSCompanionClient` (`platform: "macos"`, APNs push registration)
   - `IOSCompanionClient` (`platform: "ios"`, APNs push registration)
@@ -1201,7 +1201,7 @@ Companion runtime helper:
   - optional `defaultSessionId` for canvas helper calls so `sessionId` can be omitted per call
   - lifecycle passthroughs for connection state/teardown (`connected`, `dispose(code?, reason?)`)
   - stream passthrough helpers (`subscribeEvents`, `subscribeEvent`, `clearEventSubscriptions`, `listKnownEventNames`, `eventSubscriptionCount`, `subscribeAgentStream/Typing/ContextWarning`, `waitForEvent`, `waitForAnyEvent`, `waitForAgentStream/Typing/ContextWarning`)
-  - runtime observability passthroughs (`pendingRequestCount`, `connected`)
+  - runtime observability passthroughs (`pendingRequestCount`, `pendingEventWaitCount`, `connected`)
 - `src/companion/heartbeatLoop.ts` provides `CompanionHeartbeatLoop` for periodic heartbeat scheduling (`publishHeartbeat`) with start/stop safety, optional interval jitter (`jitterRatio`) to spread load, `tickNow()` for manual sends, success/error hooks, loop observability (`successCount`, `lastSuccessAt`, `failureCount`, `lastFailure`, `getState()`), and optional auto-stop after repeated failures.
 
 ## Canvas / A2UI Foundation

docs/plans/state.json

@@ -858,6 +858,21 @@
       ],
       "test_status": "pnpm test:run src/companion/runtimeClient.test.ts src/companion/platformClients.test.ts src/companion/heartbeatLoop.test.ts src/companion/platformClients.integration.test.ts + pnpm typecheck passing"
     },
+    "companion-runtime-pending-event-wait-observability": {
+      "status": "completed",
+      "date": "2026-02-17",
+      "updated": "2026-02-17",
+      "summary": "Added runtime `pendingEventWaitCount` observability and platform passthrough getters so companion runtimes can inspect active waiter cardinality for `waitFor*` event flows.",
+      "files_modified": [
+        "src/companion/runtimeClient.ts",
+        "src/companion/runtimeClient.test.ts",
+        "src/companion/platformClients.ts",
+        "src/companion/platformClients.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/heartbeatLoop.test.ts src/companion/platformClients.integration.test.ts + pnpm typecheck passing"
+    },
     "browser-tools-activation-clarity": {
       "status": "completed",
       "date": "2026-02-17",

src/companion/platformClients.test.ts

@@ -39,6 +39,7 @@ function createRuntimeMock(): {
   waitForAnyEvent: ReturnType<typeof vi.fn>;
   eventSubscriptionCount: number;
   pendingRequestCount: number;
+  pendingEventWaitCount: number;
   connected: boolean;
 } {
   const connect = vi.fn(async () => undefined);
@@ -79,6 +80,7 @@ function createRuntimeMock(): {
   const waitForAnyEvent = vi.fn(async () => ({ event: 'agent.stream', data: { token: 'any' } }));
   const eventSubscriptionCount = 3;
   const pendingRequestCount = 2;
+  const pendingEventWaitCount = 1;
   const connected = true;
 
   const runtime = {
@@ -117,6 +119,9 @@ function createRuntimeMock(): {
     get pendingRequestCount() {
       return pendingRequestCount;
     },
+    get pendingEventWaitCount() {
+      return pendingEventWaitCount;
+    },
     get connected() {
       return connected;
     },
@@ -155,6 +160,7 @@ function createRuntimeMock(): {
     waitForAnyEvent,
     eventSubscriptionCount,
     pendingRequestCount,
+    pendingEventWaitCount,
     connected,
   };
 }
@@ -307,6 +313,13 @@ describe('platform companion clients', () => {
     expect(client.pendingRequestCount).toBe(mock.pendingRequestCount);
   });
 
+  it('platform pendingEventWaitCount forwards runtime getter value', async () => {
+    const mock = createRuntimeMock();
+    const client = new IOSCompanionClient({ runtime: mock.runtime, nodeId: 'ios-node' });
+
+    expect(client.pendingEventWaitCount).toBe(mock.pendingEventWaitCount);
+  });
+
   it('macOS client forwards canvas methods to runtime client', async () => {
     const mock = createRuntimeMock();
     const client = new MacOSCompanionClient({ runtime: mock.runtime, nodeId: 'mac-node' });

src/companion/platformClients.ts

@@ -279,6 +279,10 @@ export class MacOSCompanionClient {
     return this.runtime.pendingRequestCount;
   }
 
+  get pendingEventWaitCount(): number {
+    return this.runtime.pendingEventWaitCount;
+  }
+
   waitForAnyEvent<TData = unknown>(
     eventNames: readonly (CompanionEventName | string)[],
     options?: {
@@ -525,6 +529,10 @@ export class IOSCompanionClient {
     return this.runtime.pendingRequestCount;
   }
 
+  get pendingEventWaitCount(): number {
+    return this.runtime.pendingEventWaitCount;
+  }
+
   waitForAnyEvent<TData = unknown>(
     eventNames: readonly (CompanionEventName | string)[],
     options?: {
@@ -769,6 +777,10 @@ export class AndroidCompanionClient {
     return this.runtime.pendingRequestCount;
   }
 
+  get pendingEventWaitCount(): number {
+    return this.runtime.pendingEventWaitCount;
+  }
+
   waitForAnyEvent<TData = unknown>(
     eventNames: readonly (CompanionEventName | string)[],
     options?: {

src/companion/runtimeClient.test.ts

@@ -305,11 +305,13 @@ describe('CompanionRuntimeClient', () => {
     const client = new CompanionRuntimeClient({
       url: 'ws://127.0.0.1:1',
     });
+    expect(client.pendingEventWaitCount).toBe(0);
 
     const awaited = client.waitForEvent<{ seq: number }>('agent.stream', {
       timeoutMs: 2000,
       predicate: (data) => data.seq === 2,
     });
+    expect(client.pendingEventWaitCount).toBe(1);
 
     (client as unknown as { handleMessage: (raw: string) => void }).handleMessage(
       JSON.stringify({
@@ -327,6 +329,7 @@ describe('CompanionRuntimeClient', () => {
     );
 
     await expect(awaited).resolves.toEqual({ seq: 2 });
+    expect(client.pendingEventWaitCount).toBe(0);
   });
 
   it('waitForEvent rejects on timeout', async () => {

src/companion/runtimeClient.ts

@@ -306,6 +306,10 @@ export class CompanionRuntimeClient {
     return this.pending.size;
   }
 
+  get pendingEventWaitCount(): number {
+    return this.pendingEventWaits.size;
+  }
+
   async connect(): Promise<void> {
     if (this.connected) {
       return;