feat(companion): add typed agent stream subscription helpers

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()`, `waitForEvent()` with timeout/predicate/abort support, `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`, `dispose()`) and event helpers (`subscribeEvents()`, `subscribeEvent()`, `subscribeAgentStream()`, `subscribeAgentTyping()`, `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

@@ -473,6 +473,20 @@
       ],
       "test_status": "pnpm test:run src/companion/platformClients.test.ts src/companion/runtimeClient.test.ts src/companion/heartbeatLoop.test.ts src/companion/platformClients.integration.test.ts + pnpm typecheck passing"
     },
+    "companion-runtime-typed-stream-subscriptions": {
+      "status": "completed",
+      "date": "2026-02-17",
+      "updated": "2026-02-17",
+      "summary": "Added typed stream-event convenience subscriptions on `CompanionRuntimeClient` (`subscribeAgentStream`, `subscribeAgentTyping`) and exported canonical event-name constants.",
+      "files_modified": [
+        "src/companion/runtimeClient.ts",
+        "src/companion/runtimeClient.test.ts",
+        "src/companion/index.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/index.ts

@@ -1,6 +1,7 @@
 export {
   CompanionRuntimeClient,
   GatewayRpcError,
+  COMPANION_EVENT_NAMES,
 } from './runtimeClient.js';
 export {
   MacOSCompanionClient,

src/companion/runtimeClient.test.ts

@@ -196,6 +196,34 @@ describe('CompanionRuntimeClient', () => {
     expect(streamHandler).toHaveBeenCalledTimes(1);
   });
 
+  it('supports subscribeAgentStream and subscribeAgentTyping helpers', () => {
+    const client = new CompanionRuntimeClient({
+      url: 'ws://127.0.0.1:1',
+    });
+    const streamHandler = vi.fn();
+    const typingHandler = vi.fn();
+    client.subscribeAgentStream(streamHandler);
+    client.subscribeAgentTyping(typingHandler);
+
+    (client as unknown as { handleMessage: (raw: string) => void }).handleMessage(
+      JSON.stringify({
+        id: 52,
+        event: 'agent.stream',
+        data: { token: 'x' },
+      }),
+    );
+    (client as unknown as { handleMessage: (raw: string) => void }).handleMessage(
+      JSON.stringify({
+        id: 53,
+        event: 'agent.typing',
+        data: { active: true },
+      }),
+    );
+
+    expect(streamHandler).toHaveBeenCalledWith({ token: 'x' });
+    expect(typingHandler).toHaveBeenCalledWith({ active: true });
+  });
+
   it('clears all event subscriptions', () => {
     const client = new CompanionRuntimeClient({
       url: 'ws://127.0.0.1:1',

src/companion/runtimeClient.ts

@@ -45,6 +45,12 @@ export type CompanionEventHandler = (event: string, data: unknown) => void;
 export type CompanionTypedEventHandler<TData = unknown> = (data: TData) => void;
 export type CompanionEventPredicate<TData = unknown> = (data: TData) => boolean;
 
+export const COMPANION_EVENT_NAMES = {
+  agentStream: 'agent.stream',
+  agentTyping: 'agent.typing',
+  contextWarning: 'context_warning',
+} as const;
+
 export interface RegisterNodeInput {
   nodeId: string;
   role: string;
@@ -385,6 +391,18 @@ export class CompanionRuntimeClient {
     });
   }
 
+  subscribeAgentStream<TData = unknown>(
+    handler: CompanionTypedEventHandler<TData>,
+  ): () => void {
+    return this.subscribeEvent<TData>(COMPANION_EVENT_NAMES.agentStream, handler);
+  }
+
+  subscribeAgentTyping<TData = unknown>(
+    handler: CompanionTypedEventHandler<TData>,
+  ): () => void {
+    return this.subscribeEvent<TData>(COMPANION_EVENT_NAMES.agentTyping, handler);
+  }
+
   waitForEvent<TData = unknown>(
     eventName: string,
     options?: {