feat(companion): validate event wait helper input names

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 and deterministic teardown cancellation (including socket-close rejection), `waitForAnyEvent()`, `waitForAgentStream()`, `waitForAgentTyping()`, `waitForContextWarning()`, `clearEventSubscriptions()`, `listKnownEventNames()`, `eventSubscriptionCount`).
+- `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`).
 - `src/companion/platformClients.ts` provides platform-focused wrappers:
   - `MacOSCompanionClient` (`platform: "macos"`, APNs push registration)
   - `IOSCompanionClient` (`platform: "ios"`, APNs push registration)

docs/plans/state.json

@@ -796,6 +796,19 @@
       ],
       "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-event-name-input-validation": {
+      "status": "completed",
+      "date": "2026-02-17",
+      "updated": "2026-02-17",
+      "summary": "Added runtime input validation for event wait helpers so `waitForEvent()` rejects empty event names and `waitForAnyEvent()` rejects lists containing empty names.",
+      "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/heartbeatLoop.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

@@ -343,6 +343,15 @@ describe('CompanionRuntimeClient', () => {
     vi.useRealTimers();
   });
 
+  it('waitForEvent validates eventName input', () => {
+    const client = new CompanionRuntimeClient({
+      url: 'ws://127.0.0.1:1',
+    });
+
+    expect(() => client.waitForEvent('')).toThrow('eventName must be a non-empty string');
+    expect(() => client.waitForEvent('   ')).toThrow('eventName must be a non-empty string');
+  });
+
   it('waitForEvent supports AbortSignal cancellation', async () => {
     const client = new CompanionRuntimeClient({
       url: 'ws://127.0.0.1:1',
@@ -573,6 +582,9 @@ describe('CompanionRuntimeClient', () => {
     expect(() => client.waitForAnyEvent([])).toThrow(
       'eventNames must contain at least one event name',
     );
+    expect(() => client.waitForAnyEvent(['agent.stream', '  '])).toThrow(
+      'eventNames must not contain empty values',
+    );
   });
 
   it('connects and performs node registration + capability discovery', async () => {

src/companion/runtimeClient.ts

@@ -437,6 +437,9 @@ export class CompanionRuntimeClient {
       signal?: AbortSignal;
     },
   ): Promise<TData> {
+    if (eventName.trim().length === 0) {
+      throw new Error('eventName must be a non-empty string');
+    }
     const timeoutMs = options?.timeoutMs ?? this.requestTimeoutMs;
     const predicate = options?.predicate;
     const signal = options?.signal;
@@ -502,6 +505,9 @@ export class CompanionRuntimeClient {
     if (eventNames.length === 0) {
       throw new Error('eventNames must contain at least one event name');
     }
+    if (eventNames.some((eventName) => eventName.trim().length === 0)) {
+      throw new Error('eventNames must not contain empty values');
+    }
     const eventNameSet = new Set(eventNames);
     const timeoutMs = options?.timeoutMs ?? this.requestTimeoutMs;
     const predicate = options?.predicate;