Model Context Protocol Multi-Server Architecture

Model Context Protocol Multi-Server Architecture An architecture diagram generated by Archify. Agent Reasoner · LangGraph Runtime · MCP Client Layer · LLM Host Agent Reasoner LangGraph Runtime LLM Host MultiServerMCPClient · Transport Router · MCP Client Layer · client.py MultiServerMCPClient Transport Router client.py ToolCallInterceptor · Token Refresh Middleware · MCP Client Layer · interceptors.py ToolCallInterceptor Token Refresh Middleware interceptors.py StdioConnection · Process stdin/stdout · Connected MCP Server Network · sessions.py StdioConnection Process stdin/stdout sessions.py SSEConnection · HTTP EventStream · Connected MCP Server Network · sessions.py SSEConnection HTTP EventStream sessions.py Filesystem MCP · Local Tools · Connected MCP Server Network · stdio pipe Filesystem MCP Local Tools stdio pipe Remote API MCP · Cloud Microservice · Connected MCP Server Network · HTTP/SSE Remote API MCP Cloud Microservice HTTP/SSE Tool Adapter · Pydantic Schema Synth · Connected MCP Server Network · tools.py Tool Adapter Pydantic Schema Synth tools.py get_tools() authorize pipe IPC stream SSE spawn subproc JSON-RPC post schema manifest schema manifest MCP Client Layer Connected MCP Server Network Legend Backend Database Cloud Security

Multiplexed Transport Support

  • • Concurrent handling of stdio child processes, HTTP SSE streams, and WebSockets
  • • Unified get_tools() discovery interface aggregating tools across distinct servers

Dynamic Schema Translation

  • • Synthesizes Pydantic input models directly from JSON Schema properties
  • • Binds validation logic to LangChain BaseTool instances at runtime

Interceptor Middleware

  • • Transparently injects authorization headers into outbound requests
  • • Handles OAuth token refreshing on 401 Unauthorized responses