Address PR review feedback

- Remove unused session2 variable in multi-client test
- Document fire-and-forget semantics in _handleBroadcastEvent
- Fix null/undefined handling in tool result serialization
- Fix stale RPC method names in comment

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: SteveSandersonMS

nodejs/src/client.ts

@@ -1307,7 +1307,8 @@ export class CopilotClient {
         // External tool calls and permission requests are now handled via broadcast events:
         // the server sends external_tool.requested / permission.requested as session event
         // notifications, and CopilotSession._dispatchEvent handles them internally by
-        // executing the handler and responding via session.tools.respond / session.permissions.respond RPC.
+        // executing the handler and responding via session.tools.handlePendingToolCall /
+        // session.permissions.handlePendingPermissionRequest RPC.
 
         this.connection.onRequest(
             "userInput.request",

nodejs/src/session.ts

@@ -316,6 +316,8 @@ export class CopilotSession {
 
     /**
      * Handles broadcast request events by executing local handlers and responding via RPC.
+     * Handlers are dispatched as fire-and-forget — rejections propagate as unhandled promise
+     * rejections, consistent with standard EventEmitter / event handler semantics.
      * @internal
      */
     private _handleBroadcastEvent(event: SessionEvent): void {
@@ -362,10 +364,14 @@ export class CopilotSession {
                 toolName,
                 arguments: args,
             });
-            const result =
-                typeof rawResult === "string"
-                    ? rawResult
-                    : JSON.stringify(rawResult ?? "");
+            let result: string;
+            if (rawResult == null) {
+                result = "";
+            } else if (typeof rawResult === "string") {
+                result = rawResult;
+            } else {
+                result = JSON.stringify(rawResult);
+            }
             await this.rpc.tools.handlePendingToolCall({ requestId, result });
         } catch (error) {
             const message =

nodejs/test/e2e/multi-client.test.ts

@@ -255,7 +255,7 @@ describe("Multi-client broadcast", async () => {
         });
 
         // Client 2 resumes with ephemeral_tool
-        const session2 = await client2.resumeSession(session1.sessionId, {
+        await client2.resumeSession(session1.sessionId, {
             onPermissionRequest: approveAll,
             tools: [toolB],
         });