diff --git a/src/components/app-builder/project-manager/sessions/v2/streaming.ts b/src/components/app-builder/project-manager/sessions/v2/streaming.ts
index fdf327183..2cf8e703f 100644
--- a/src/components/app-builder/project-manager/sessions/v2/streaming.ts
+++ b/src/components/app-builder/project-manager/sessions/v2/streaming.ts
@@ -180,7 +180,7 @@ export function createV2StreamingCoordinator(config: V2StreamingConfig): V2Strea
         });
       },
 
-      onSessionStatusChanged: status => {
+      onSessionStatusChanged: (status, _eventSessionId) => {
         if (status.type === 'idle') {
           store.setState({ isStreaming: false });
           onStreamComplete?.();
diff --git a/src/components/cloud-agent-next/useCloudAgentStream.ts b/src/components/cloud-agent-next/useCloudAgentStream.ts
index 7ac88150f..89a3c270d 100644
--- a/src/components/cloud-agent-next/useCloudAgentStream.ts
+++ b/src/components/cloud-agent-next/useCloudAgentStream.ts
@@ -239,7 +239,7 @@ export function useCloudAgentStream({
         }
       },
 
-      onSessionStatusChanged: status => {
+      onSessionStatusChanged: (status, _eventSessionId) => {
         setSessionStatus(status);
 
         // Handle streaming state based on status
diff --git a/src/lib/cloud-agent-next/processor/event-processor.test.ts b/src/lib/cloud-agent-next/processor/event-processor.test.ts
index eb26c6252..ad865f764 100644
--- a/src/lib/cloud-agent-next/processor/event-processor.test.ts
+++ b/src/lib/cloud-agent-next/processor/event-processor.test.ts
@@ -441,7 +441,10 @@ describe('createEventProcessor', () => {
         })
       );
 
-      expect(callbacks.onSessionStatusChanged).toHaveBeenCalledWith({ type: 'busy' });
+      expect(callbacks.onSessionStatusChanged).toHaveBeenCalledWith(
+        { type: 'busy' },
+        'session-123'
+      );
       expect(callbacks.onStreamingChanged).toHaveBeenCalledWith(true);
     });
 
@@ -468,7 +471,10 @@ describe('createEventProcessor', () => {
         })
       );
 
-      expect(callbacks.onSessionStatusChanged).toHaveBeenLastCalledWith({ type: 'idle' });
+      expect(callbacks.onSessionStatusChanged).toHaveBeenLastCalledWith(
+        { type: 'idle' },
+        'session-123'
+      );
       expect(callbacks.onStreamingChanged).toHaveBeenLastCalledWith(false);
     });
 
diff --git a/src/lib/cloud-agent-next/processor/event-processor.ts b/src/lib/cloud-agent-next/processor/event-processor.ts
index b745ca8e2..d41465468 100644
--- a/src/lib/cloud-agent-next/processor/event-processor.ts
+++ b/src/lib/cloud-agent-next/processor/event-processor.ts
@@ -309,9 +309,9 @@ export function createEventProcessor(config: EventProcessorConfig = {}): EventPr
    * Handle session.status events.
    */
   function handleSessionStatus(data: EventSessionStatus['properties']): void {
-    const { status } = data;
+    const { sessionID, status } = data;
 
-    callbacks.onSessionStatusChanged?.(status);
+    callbacks.onSessionStatusChanged?.(status, sessionID);
 
     // Update streaming state based on status
     if (status.type === 'idle') {
diff --git a/src/lib/cloud-agent-next/processor/types.ts b/src/lib/cloud-agent-next/processor/types.ts
index 7fd73e911..f8bf7b641 100644
--- a/src/lib/cloud-agent-next/processor/types.ts
+++ b/src/lib/cloud-agent-next/processor/types.ts
@@ -69,8 +69,8 @@ export type EventProcessorCallbacks = {
     parentSessionId: string | null
   ) => void;
 
-  /** Called when session status changes (idle/busy/retry) */
-  onSessionStatusChanged?: (status: SessionStatus) => void;
+  /** Called when session status changes (idle/busy/retry). sessionID identifies which session changed. */
+  onSessionStatusChanged?: (status: SessionStatus, sessionID: string) => void;
 
   /** Called when a new session is created (session.created event) */
   onSessionCreated?: (sessionInfo: Session) => void;
diff --git a/src/lib/cloud-agent-next/run-session.ts b/src/lib/cloud-agent-next/run-session.ts
index 3fd979720..f4eb013c4 100644
--- a/src/lib/cloud-agent-next/run-session.ts
+++ b/src/lib/cloud-agent-next/run-session.ts
@@ -242,8 +242,11 @@ export async function runSessionToCompletion(input: RunSessionInput): Promise<Ru
           errorMessage = errData?.data?.message ?? 'Assistant message failed.';
         }
       },
-      onSessionStatusChanged: status => {
-        if (status.type === 'idle') resolveOnce();
+      onSessionStatusChanged: (status, eventSessionId) => {
+        // Only resolve when the *root* session goes idle. Subagent (child)
+        // sessions also emit idle events; resolving on those would cause
+        // the orchestrator to return a partial result prematurely.
+        if (status.type === 'idle' && eventSessionId === sessionId) resolveOnce();
       },
       onError: error => {
         hasError = true;