fix: address code review feedback from coderabbitai

- Add language specifier to fenced code block in expand-project.md
- Remove detailed exception strings from WebSocket responses (security)
- Make WebSocket "start" message idempotent to avoid session reset
- Fix race condition in bulk feature creation with row-level lock
- Add validation for starting_priority (must be >= 1)
- Fix _query_claude to handle multiple feature blocks and deduplicate
- Add FileReader error handling in ExpandProjectChat
- Fix disconnect() to clear pending reconnect timeout
- Enable sandbox mode and validate CLI path in expand_chat_session
- Clean up temporary settings file on session close

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

.claude/commands/expand-project.md

@@ -144,7 +144,7 @@ Once the user approves, create features directly.
 
 **Then output the features in this exact JSON format (the system will parse this):**
 
-```
+```json
 <features_to_create>
 [
   {

server/routers/expand_project.py

@@ -161,12 +161,22 @@ async def expand_project_websocket(websocket: WebSocket, project_name: str):
                     continue
 
                 elif msg_type == "start":
-                    # Create and start a new expansion session
-                    session = await create_expand_session(project_name, project_dir)
+                    # Check if session already exists (idempotent start)
+                    existing_session = get_expand_session(project_name)
+                    if existing_session:
+                        session = existing_session
+                        await websocket.send_json({
+                            "type": "text",
+                            "content": "Resuming existing expansion session. What would you like to add?"
+                        })
+                        await websocket.send_json({"type": "response_done"})
+                    else:
+                        # Create and start a new expansion session
+                        session = await create_expand_session(project_name, project_dir)
 
-                    # Stream the initial greeting
-                    async for chunk in session.start():
-                        await websocket.send_json(chunk)
+                        # Stream the initial greeting
+                        async for chunk in session.start():
+                            await websocket.send_json(chunk)
 
                 elif msg_type == "message":
                     # User sent a message
@@ -192,7 +202,7 @@ async def expand_project_websocket(websocket: WebSocket, project_name: str):
                             logger.warning(f"Invalid attachment data: {e}")
                             await websocket.send_json({
                                 "type": "error",
-                                "content": f"Invalid attachment: {str(e)}"
+                                "content": "Invalid attachment format"
                             })
                             continue
 
@@ -236,7 +246,7 @@ async def expand_project_websocket(websocket: WebSocket, project_name: str):
         try:
             await websocket.send_json({
                 "type": "error",
-                "content": f"Server error: {str(e)}"
+                "content": "Internal server error"
             })
         except Exception:
             pass

server/routers/features.py

@@ -305,7 +305,7 @@ async def create_features_bulk(project_name: str, bulk: FeatureBulkCreate):
     Create multiple features at once.
 
     Features are assigned sequential priorities starting from:
-    - starting_priority if specified
+    - starting_priority if specified (must be >= 1)
     - max(existing priorities) + 1 if not specified
 
     This is useful for:
@@ -328,18 +328,28 @@ async def create_features_bulk(project_name: str, bulk: FeatureBulkCreate):
     if not bulk.features:
         return FeatureBulkCreateResponse(created=0, features=[])
 
+    # Validate starting_priority if provided
+    if bulk.starting_priority is not None and bulk.starting_priority < 1:
+        raise HTTPException(status_code=400, detail="starting_priority must be >= 1")
+
     _, Feature = _get_db_classes()
 
     try:
         with get_db_session(project_dir) as session:
-            # Determine starting priority
+            # Determine starting priority with row-level lock to prevent race conditions
             if bulk.starting_priority is not None:
                 current_priority = bulk.starting_priority
             else:
-                max_priority_feature = session.query(Feature).order_by(Feature.priority.desc()).first()
+                # Lock the max priority row to prevent concurrent inserts from getting same priority
+                max_priority_feature = (
+                    session.query(Feature)
+                    .order_by(Feature.priority.desc())
+                    .with_for_update()
+                    .first()
+                )
                 current_priority = (max_priority_feature.priority + 1) if max_priority_feature else 1
 
-            created_features = []
+            created_ids = []
 
             for feature_data in bulk.features:
                 db_feature = Feature(
@@ -351,20 +361,16 @@ async def create_features_bulk(project_name: str, bulk: FeatureBulkCreate):
                     passes=False,
                 )
                 session.add(db_feature)
+                session.flush()  # Flush to get the ID immediately
+                created_ids.append(db_feature.id)
                 current_priority += 1
 
             session.commit()
 
-            # Refresh to get IDs and return responses
-            for db_feature in session.query(Feature).order_by(Feature.priority.desc()).limit(len(bulk.features)).all():
-                created_features.insert(0, feature_to_response(db_feature))
-
-            # Re-query to get the actual created features in order
+            # Query created features by their IDs (avoids relying on priority range)
             created_features = []
-            start_priority = current_priority - len(bulk.features)
             for db_feature in session.query(Feature).filter(
-                Feature.priority >= start_priority,
-                Feature.priority < current_priority
+                Feature.id.in_(created_ids)
             ).order_by(Feature.priority).all():
                 created_features.append(feature_to_response(db_feature))
 

server/services/expand_chat_session.py

@@ -67,6 +67,7 @@ class ExpandChatSession:
         self._client_entered: bool = False
         self.features_created: int = 0
         self.created_feature_ids: list[int] = []
+        self._settings_file: Optional[Path] = None
 
     async def close(self) -> None:
         """Clean up resources and close the Claude client."""
@@ -79,6 +80,13 @@ class ExpandChatSession:
                 self._client_entered = False
                 self.client = None
 
+        # Clean up temporary settings file
+        if self._settings_file and self._settings_file.exists():
+            try:
+                self._settings_file.unlink()
+            except Exception as e:
+                logger.warning(f"Error removing settings file: {e}")
+
     async def start(self) -> AsyncGenerator[dict, None]:
         """
         Initialize session and get initial greeting from Claude.
@@ -111,7 +119,7 @@ class ExpandChatSession:
 
         # Create security settings file
         security_settings = {
-            "sandbox": {"enabled": False},
+            "sandbox": {"enabled": True},
             "permissions": {
                 "defaultMode": "acceptEdits",
                 "allow": [
@@ -121,6 +129,7 @@ class ExpandChatSession:
             },
         }
         settings_file = self.project_dir / ".claude_settings.json"
+        self._settings_file = settings_file
         with open(settings_file, "w") as f:
             json.dump(security_settings, f, indent=2)
 
@@ -128,8 +137,14 @@ class ExpandChatSession:
         project_path = str(self.project_dir.resolve())
         system_prompt = skill_content.replace("$ARGUMENTS", project_path)
 
-        # Create Claude SDK client
+        # Find and validate Claude CLI
         system_cli = shutil.which("claude")
+        if not system_cli:
+            yield {
+                "type": "error",
+                "content": "Claude CLI not found. Please install Claude Code."
+            }
+            return
         try:
             self.client = ClaudeSDKClient(
                 options=ClaudeAgentOptions(
@@ -268,20 +283,35 @@ class ExpandChatSession:
                                 "timestamp": datetime.now().isoformat()
                             })
 
-        # Check for feature creation block in full response
-        features_match = re.search(
+        # Check for feature creation blocks in full response (handle multiple blocks)
+        features_matches = re.findall(
             r'<features_to_create>\s*(\[[\s\S]*?\])\s*</features_to_create>',
             full_response
         )
 
-        if features_match:
-            try:
-                features_json = features_match.group(1)
-                features_data = json.loads(features_json)
+        if features_matches:
+            # Collect all features from all blocks, deduplicating by name
+            all_features: list[dict] = []
+            seen_names: set[str] = set()
 
-                if features_data and isinstance(features_data, list):
-                    # Create features via REST API
-                    created = await self._create_features_bulk(features_data)
+            for features_json in features_matches:
+                try:
+                    features_data = json.loads(features_json)
+
+                    if features_data and isinstance(features_data, list):
+                        for feature in features_data:
+                            name = feature.get("name", "")
+                            if name and name not in seen_names:
+                                seen_names.add(name)
+                                all_features.append(feature)
+                except json.JSONDecodeError as e:
+                    logger.error(f"Failed to parse features JSON block: {e}")
+                    # Continue processing other blocks
+
+            if all_features:
+                try:
+                    # Create all deduplicated features
+                    created = await self._create_features_bulk(all_features)
 
                     if created:
                         self.features_created += len(created)
@@ -294,18 +324,12 @@ class ExpandChatSession:
                         }
 
                         logger.info(f"Created {len(created)} features for {self.project_name}")
-            except json.JSONDecodeError as e:
-                logger.error(f"Failed to parse features JSON: {e}")
-                yield {
-                    "type": "error",
-                    "content": f"Failed to parse feature definitions: {str(e)}"
-                }
-            except Exception as e:
-                logger.exception("Failed to create features")
-                yield {
-                    "type": "error",
-                    "content": f"Failed to create features: {str(e)}"
-                }
+                except Exception as e:
+                    logger.exception("Failed to create features")
+                    yield {
+                        "type": "error",
+                        "content": "Failed to create features"
+                    }
 
     async def _create_features_bulk(self, features: list[dict]) -> list[dict]:
         """

ui/src/components/ExpandProjectChat.tsx

@@ -121,6 +121,9 @@ export function ExpandProjectChat({
 
         setPendingAttachments((prev) => [...prev, attachment])
       }
+      reader.onerror = () => {
+        setError(`Failed to read file: ${file.name}`)
+      }
       reader.readAsDataURL(file)
     })
   }, [])

ui/src/hooks/useExpandChat.ts

@@ -302,6 +302,10 @@ export function useExpandChat({
       clearInterval(pingIntervalRef.current)
       pingIntervalRef.current = null
     }
+    if (reconnectTimeoutRef.current) {
+      clearTimeout(reconnectTimeoutRef.current)
+      reconnectTimeoutRef.current = null
+    }
     if (wsRef.current) {
       wsRef.current.close()
       wsRef.current = null