Add two new middlewares to improve robustness of the agent pipeline:
- DanglingToolCallMiddleware injects placeholder ToolMessages for
interrupted tool calls, preventing LLM errors from malformed history
- SubagentLimitMiddleware truncates excess parallel task tool calls at
the model response level, replacing the runtime check in task_tool
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Prevent resource exhaustion by capping the number of parallel subagents.
Adds runtime enforcement in task_tool and updates prompts/examples accordingly.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Enable task tool to capture and stream AI messages as they are generated by subagents. This replaces simple polling status updates with detailed message-level progress updates.
Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
- Reorder task tool parameters to prioritize description first for better usability
- Add tool_call_id injection for better task traceability
- Use tool_call_id as task_id in executor for consistent tracking
- Simplify event messages by removing redundant task_type field
- Update task examples in prompt to reflect new parameter order
Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
Add subagents.enabled flag in config.yaml to control subagent feature:
- When disabled, task/task_status tools are not loaded
- When disabled, system prompt excludes subagent documentation
- Default is enabled for backward compatibility
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
- Add model-aware vision tool loading based on supports_vision flag
- Move view_image_tool from config to builtin tools for dynamic inclusion
- Add timeout to image search to prevent hanging requests
- Optimize image search results format using thumbnails
- Add image validation for reference images in generation
- Improve error handling with detailed messages
Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
Add image viewing capability for vision-enabled models with ViewImageMiddleware and view_image_tool. Limit web_fetch tool output to 4096 characters to prevent excessive content. Update model config to support vision capability flag.
Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
- Use ExtensionsConfig.from_file() instead of cached config to always
read latest configuration from disk in LangGraph Server
- Add mtime-based cache invalidation for MCP tools to detect config
file changes made through Gateway API
- Call reload_extensions_config() in Gateway API after updates to
refresh the global cache
- Remove unnecessary MCP initialization from Gateway startup since
MCP tools are only used by LangGraph Server
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
- Add type, url, and headers fields to MCP server config
- Update MCP client to handle stdio, sse, and http transports
- Add todos field to ThreadState
- Add Deerflow branding requirement to frontend-design skill
- Update extensions_config.example.json with SSE/HTTP examples
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
Add comprehensive MCP integration using langchain-mcp-adapters to enable
pluggable external tools from MCP servers.
Features:
- MCP server configuration via mcp_config.json
- Automatic lazy initialization for seamless use in both FastAPI and LangGraph Studio
- Support for multiple MCP servers (filesystem, postgres, github, brave-search, etc.)
- Environment variable resolution in configuration
- Tool caching mechanism for optimal performance
- Complete documentation and setup guide
Implementation:
- Add src/mcp module with client, tools, and cache components
- Integrate MCP config loading in AppConfig
- Update tool system to include MCP tools automatically
- Add eager initialization in FastAPI lifespan handler
- Add lazy initialization fallback for LangGraph Studio
Dependencies:
- Add langchain-mcp-adapters>=0.1.0
Documentation:
- Add MCP_SETUP.md with comprehensive setup guide
- Update CLAUDE.md with MCP system architecture
- Update config.example.yaml with MCP configuration notes
- Update README.md with MCP setup instructions
Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
