Debug-MCP

Instructions

Implementation Reference

• src/mcp_debug_tool/server.py:499-553 (handler)

  MCP tool handler for 'sessions_end': validates sessionId, calls SessionManager.end_session_async(), handles errors, returns JSON response as TextContent.
  async def _handle_sessions_end(self, arguments: dict) -> list[TextContent]: """ Handler for sessions_end tool. Ends a debug session and cleans up resources. """ try: session_id = arguments.get("sessionId") if not session_id: return [ TextContent( type="text", text=json.dumps({ "error": { "type": "ValueError", "message": "sessionId is required", } }), ) ] response = await self.session_manager.end_session_async(session_id) result = response.model_dump() return [ TextContent( type="text", text=json.dumps(result), ) ] except KeyError as e: return [ TextContent( type="text", text=json.dumps({ "error": { "type": "SessionNotFound", "message": str(e), } }), ) ] except Exception as e: logger.exception("Error ending session") return [ TextContent( type="text", text=json.dumps({ "error": { "type": type(e).__name__, "message": str(e), } }), ) ]
• src/mcp_debug_tool/server.py:148-161 (registration)

  Tool registration in list_tools(): defines name, description, and inputSchema requiring 'sessionId' string.
  Tool( name="sessions_end", description="End a debug session and clean up resources", inputSchema={ "type": "object", "properties": { "sessionId": { "type": "string", "description": "The debug session ID", }, }, "required": ["sessionId"], }, ),
• src/mcp_debug_tool/schemas.py:161-164 (schema)

  Pydantic model for output response: simple confirmation {ended: true}.
  class EndSessionResponse(BaseModel): """Response confirming session ended.""" ended: bool = True
• src/mcp_debug_tool/sessions.py:219-264 (helper)

  Core SessionManager.end_session(): terminates DAP wrapper or subprocess, updates status to COMPLETED, removes session from manager.
  def end_session(self, session_id: str) -> EndSessionResponse: """ End a debug session and clean up resources. Args: session_id: Session ID Returns: End confirmation response """ session = self.get_session(session_id) # Clean up DAP wrapper if using DAP if session.dap_wrapper: try: session.dap_wrapper.terminate() except Exception: pass # Clean up subprocess if running (bdb mode) if session.process and session.process.poll() is None: # Try graceful termination first try: terminate_cmd = json.dumps({"command": "terminate"}) + '\n' session.process.stdin.write(terminate_cmd) session.process.stdin.flush() session.process.wait(timeout=5) except Exception: pass # Force terminate if still running if session.process.poll() is None: session.process.terminate() try: session.process.wait(timeout=5) except subprocess.TimeoutExpired: session.process.kill() session.process.wait() # Update status session.update_status(SessionStatus.COMPLETED) # Remove from active sessions del self.sessions[session_id] return EndSessionResponse(ended=True)
• src/mcp_debug_tool/sessions.py:946-952 (helper)

  Async wrapper end_session_async(): bridges sync end_session to async MCP handler via asyncio.to_thread.
  async def end_session_async(self, session_id: str) -> EndSessionResponse: """ Async wrapper for end_session. Runs the synchronous end_session in a thread pool to avoid blocking. """ return await asyncio.to_thread(self.end_session, session_id)