fix: return empty skills/hooks list instead of 404 for stopped sandboxes

When opening a previously closed conversation, the skills and hooks
endpoints were returning 404 because the sandbox is not running.
This is incorrect - a closed conversation is still valid, it just
doesn't have active skills/hooks.

Fix by modifying _get_agent_server_context to return None when
sandbox is paused/error/missing (closed conversation), and having
endpoints return empty lists. Keep 404 for STARTING state so
frontend knows to retry.

Co-authored-by: openhands <openhands@all-hands.dev>

openhands/app_server/app_conversation/app_conversation_router.py

@@ -115,7 +115,7 @@ async def _get_agent_server_context(
     app_conversation_service: AppConversationService,
     sandbox_service: SandboxService,
     sandbox_spec_service: SandboxSpecService,
-) -> AgentServerContext | JSONResponse:
+) -> AgentServerContext | JSONResponse | None:
     """Get the agent server context for a conversation.
 
     This helper retrieves all necessary information to communicate with the
@@ -129,7 +129,8 @@ async def _get_agent_server_context(
         sandbox_spec_service: Service for sandbox spec operations
 
     Returns:
-        AgentServerContext if successful, or JSONResponse with error details.
+        AgentServerContext if successful, JSONResponse(404) if conversation
+        not found, or None if sandbox is not running (e.g. closed conversation).
     """
     # Get the conversation info
     conversation = await app_conversation_service.get_app_conversation(conversation_id)
@@ -141,12 +142,20 @@ async def _get_agent_server_context(
 
     # Get the sandbox info
     sandbox = await sandbox_service.get_sandbox(conversation.sandbox_id)
-    if not sandbox or sandbox.status != SandboxStatus.RUNNING:
+    if not sandbox:
+        return None
+    # Return None for paused/error/missing sandboxes (closed conversation)
+    if sandbox.status in (
+        SandboxStatus.PAUSED,
+        SandboxStatus.ERROR,
+        SandboxStatus.MISSING,
+    ):
+        return None
+    # Return 404 for STARTING state (sandbox not ready yet)
+    if sandbox.status != SandboxStatus.RUNNING:
         return JSONResponse(
             status_code=status.HTTP_404_NOT_FOUND,
-            content={
-                'error': f'Sandbox not found or not running for conversation {conversation_id}'
-            },
+            content={'error': f'Sandbox not ready for conversation {conversation_id}'},
         )
 
     # Get the sandbox spec to find the working directory
@@ -587,6 +596,7 @@ async def get_conversation_skills(
 
     Returns:
         JSONResponse: A JSON response containing the list of skills.
+        Returns an empty list if the sandbox is not running.
     """
     try:
         # Get agent server context (conversation, sandbox, sandbox_spec, agent_server_url)
@@ -598,6 +608,8 @@ async def get_conversation_skills(
         )
         if isinstance(ctx, JSONResponse):
             return ctx
+        if ctx is None:
+            return JSONResponse(status_code=status.HTTP_200_OK, content={'skills': []})
 
         # Load skills from all sources
         logger.info(f'Loading skills for conversation {conversation_id}')
@@ -685,6 +697,7 @@ async def get_conversation_hooks(
 
     Returns:
         JSONResponse: A JSON response containing the list of hook event types.
+        Returns an empty list if the sandbox is not running.
     """
     try:
         # Get agent server context (conversation, sandbox, sandbox_spec, agent_server_url)
@@ -696,6 +709,8 @@ async def get_conversation_hooks(
         )
         if isinstance(ctx, JSONResponse):
             return ctx
+        if ctx is None:
+            return JSONResponse(status_code=status.HTTP_200_OK, content={'hooks': []})
 
         from openhands.app_server.app_conversation.hook_loader import (
             fetch_hooks_from_agent_server,

tests/unit/app_server/test_app_conversation_hooks_endpoint.py

@@ -263,7 +263,7 @@ class TestGetConversationHooks:
 
         assert response.status_code == status.HTTP_404_NOT_FOUND
 
-    async def test_get_hooks_returns_404_when_sandbox_not_running(self):
+    async def test_get_hooks_returns_empty_list_when_sandbox_not_running(self):
         conversation_id = uuid4()
         sandbox_id = str(uuid4())
 
@@ -290,4 +290,8 @@ class TestGetConversationHooks:
             httpx_client=AsyncMock(spec=httpx.AsyncClient),
         )
 
-        assert response.status_code == status.HTTP_404_NOT_FOUND
+        assert response.status_code == status.HTTP_200_OK
+        import json
+
+        data = json.loads(response.body.decode('utf-8'))
+        assert data == {'hooks': []}

tests/unit/app_server/test_app_conversation_skills_endpoint.py

@@ -198,12 +198,12 @@ class TestGetConversationSkills:
         assert 'error' in data
         assert str(conversation_id) in data['error']
 
-    async def test_get_skills_returns_404_when_sandbox_not_found(self):
-        """Test endpoint returns 404 when sandbox doesn't exist.
+    async def test_get_skills_returns_empty_list_when_sandbox_not_found(self):
+        """Test endpoint returns empty skills when sandbox doesn't exist.
 
         Arrange: Setup conversation but no sandbox
         Act: Call get_conversation_skills endpoint
-        Assert: Response is 404 with sandbox error message
+        Assert: Response is 200 with empty skills list
         """
         # Arrange
         conversation_id = uuid4()
@@ -236,20 +236,19 @@ class TestGetConversationSkills:
         )
 
         # Assert
-        assert response.status_code == status.HTTP_404_NOT_FOUND
+        assert response.status_code == status.HTTP_200_OK
         content = response.body.decode('utf-8')
         import json
 
         data = json.loads(content)
-        assert 'error' in data
-        assert 'Sandbox not found' in data['error']
+        assert data == {'skills': []}
 
-    async def test_get_skills_returns_404_when_sandbox_not_running(self):
-        """Test endpoint returns 404 when sandbox is not in RUNNING state.
+    async def test_get_skills_returns_empty_list_when_sandbox_not_running(self):
+        """Test endpoint returns empty skills when sandbox is not in RUNNING state.
 
         Arrange: Setup conversation with stopped sandbox
         Act: Call get_conversation_skills endpoint
-        Assert: Response is 404 with sandbox not running message
+        Assert: Response is 200 with empty skills list
         """
         # Arrange
         conversation_id = uuid4()
@@ -290,13 +289,12 @@ class TestGetConversationSkills:
         )
 
         # Assert
-        assert response.status_code == status.HTTP_404_NOT_FOUND
+        assert response.status_code == status.HTTP_200_OK
         content = response.body.decode('utf-8')
         import json
 
         data = json.loads(content)
-        assert 'error' in data
-        assert 'not running' in data['error']
+        assert data == {'skills': []}
 
     async def test_get_skills_handles_task_trigger_skills(self):
         """Test endpoint correctly handles skills with TaskTrigger.