MCP endpoint

initialize

Negotiate the MCP protocol version and read the CoreSpeed server capabilities.

POSThttps://api.corespeed.io/mcpinitialize

Most MCP clients send this automatically as their first call. It negotiates the protocol version and reports which capabilities the server exposes. The result can also carry instructions: guidance the agent reads at session start, on memory recall and, where Smart Approvals is available, on approvals.

A client on protocol revision 2026-07-28 does not send initialize. It sends a per-request _meta envelope instead, and reads the same capabilities and instructions from server/discover.

Authorizations

Authorizationstringheaderrequired

Bearer <token> — an MCP OAuth token, an sk-cs-… API key or sk-csa-… agent key, or a user session JWT. x-api-key: <sk-cs-…> is accepted in its place.

Acceptstringheaderrequired

application/json, text/event-stream — the Streamable HTTP transport requires both media types. This 2025-era request is answered as one text/event-stream event; its data: line is the JSON-RPC response.

Content-Typestringheaderrequired

application/json. The transport rejects anything else with 415.

Request

protocolVersionstringrequired

The version your client speaks. Supported: 2025-11-25 (latest), 2025-06-18, 2025-03-26, 2024-11-05, 2024-10-07. An unsupported value is answered with the latest version instead of an error, so read the version in the response rather than assuming yours was accepted.

capabilitiesobjectrequired

Client capabilities. Send {} when your client has none to advertise.

clientInfoobjectrequired

{ "name": string, "version": string }. Part of the MCP handshake; the gateway does not copy it onto activity events, which are emitted per tools/call.

curl https://api.corespeed.io/mcp \
  -H "Authorization: Bearer $CORESPEED_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Accept: application/json, text/event-stream" \
  -d '{
    "jsonrpc": "2.0",
    "id": 1,
    "method": "initialize",
    "params": {
      "protocolVersion": "2025-06-18",
      "capabilities": {},
      "clientInfo": { "name": "my-agent", "version": "1.0.0" }
    }
  }'
Session negotiated
{
  "jsonrpc": "2.0",
  "id": 1,
  "result": {
    "protocolVersion": "2025-06-18",
    "capabilities": {
      "tools": { "listChanged": true }
    },
    "serverInfo": {
      "name": "mcp-gateway",
      "version": "1.0.0"
    },
    "instructions": "Persistent cross-session memory is connected (the memory__* tools). …"
  }
}