Send MCP message via SSE connection

POST 
/mcp/messages

Processes MCP messages sent by the client as part of an established SSE connection. This endpoint is the client-to-server counterpart of the SSE stream, completing the bi-directional communication channel. Clients must include their session ID (received when establishing the SSE connection) either as a query parameter or in the 'mcp-session-id' header. Messages follow the standard MCP/JSON-RPC 2.0 format and are processed similarly to the regular /mcp endpoint.

Request

Responses

200

Message processed successfully

400

Bad request, missing session ID or invalid message format

404

Session not found or expired

500

Server error occurred while processing the message