> ## Documentation Index > Fetch the complete documentation index at: https://xata.io/docs/llms.txt > Use this file to discover all available pages before exploring further. # Send an MCP message > Handle a single JSON-RPC 2.0 message from an MCP client, per the MCP [Streamable HTTP transport](https://modelcontextprotocol.io/specification/2025-06-18/basic/transports). The server is stateless: every request is self-contained and carries the caller's credential, so there is no session to establish or resume. `GET` and `DELETE` on this path return `405 Method Not Allowed`. **Requests** (messages with an `id`) are answered with the JSON-RPC response, either as `application/json` or as a `text/event-stream` carrying the response and any notifications emitted while it runs. Requests must accept both. **Notifications and responses** (messages without an `id`) are answered with `202 Accepted` and an empty body. ## OpenAPI ````yaml https://api.xata.tech/openapi.json post /mcp openapi: 3.0.0 info: title: Xata API description: Xata API version: '1.0' contact: name: help@xata.io servers: - url: https://api.xata.tech description: Xata API security: [] tags: - name: Organizations description: Operations for creating, retrieving, updating, and deleting organizations x-displayName: Organizations - name: Users description: Operations for managing user accounts and profiles x-displayName: Users - name: API Keys description: >- Operations for managing API keys, including creation, listing, and deletion x-displayName: API Keys - name: Marketplace description: Operations for linking user accounts to cloud marketplace subscriptions x-displayName: Marketplace - name: Billing description: Internal organization billing operations x-displayName: Billing - name: Gateway description: >- PostgreSQL connectivity via HTTP SQL, WebSocket wire protocol proxy, and native wire protocol. x-displayName: Gateway - name: MCP description: Model Context Protocol endpoint. x-displayName: MCP - name: Projects Webhooks x-displayName: Projects Webhooks - name: Projects description: >- Operations for creating, retrieving, updating, and deleting projects within an organization x-displayName: Projects - name: Branches description: >- Operations for managing database branches within projects, including creation, configuration, and deletion x-displayName: Branches - name: GitHub App description: Operations for managing GitHub App installation mappings x-displayName: GitHub App - name: Metrics description: Operations for retrieving observability metrics for a branch x-displayName: Metrics - name: Logs description: Operations for retrieving log entries for a branch x-displayName: Logs - name: Vercel x-displayName: Vercel - name: Webhooks x-displayName: Webhooks externalDocs: url: https://xata.io/docs/api paths: /mcp: post: tags: - MCP summary: Send an MCP message description: > Handle a single JSON-RPC 2.0 message from an MCP client, per the MCP [Streamable HTTP transport](https://modelcontextprotocol.io/specification/2025-06-18/basic/transports). The server is stateless: every request is self-contained and carries the caller's credential, so there is no session to establish or resume. `GET` and `DELETE` on this path return `405 Method Not Allowed`. **Requests** (messages with an `id`) are answered with the JSON-RPC response, either as `application/json` or as a `text/event-stream` carrying the response and any notifications emitted while it runs. Requests must accept both. **Notifications and responses** (messages without an `id`) are answered with `202 Accepted` and an empty body. operationId: sendMcpRequest parameters: - name: Accept in: header description: Must list both `application/json` and `text/event-stream`. required: true schema: type: string default: application/json, text/event-stream - name: MCP-Protocol-Version in: header description: > Protocol revision negotiated during `initialize`, echoed on every subsequent request. Omitted on the `initialize` request itself. required: false schema: type: string example: '2025-06-18' requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/JSONRPCMessage' examples: initialize: summary: Start a session and learn the server's capabilities value: jsonrpc: '2.0' id: 1 method: initialize params: protocolVersion: '2025-06-18' capabilities: {} clientInfo: name: my-client version: 1.0.0 toolsList: summary: List the available tools value: jsonrpc: '2.0' id: 2 method: tools/list toolsCall: summary: Call a tool value: jsonrpc: '2.0' id: 3 method: tools/call params: name: search_operations arguments: query: list branches responses: '200': description: JSON-RPC response to the request content: application/json: schema: $ref: '#/components/schemas/JSONRPCResponse' examples: toolsCall: summary: Result of the tool call above value: jsonrpc: '2.0' id: 3 result: content: - text: >- {"operations":[{"operationID":"listBranches","method":"GET","path":"/organizations/{organizationID}/projects/{projectID}/branches","summary":"List all branches","callTool":"call_read_operation"}]} type: text isError: false text/event-stream: schema: description: >- Server-sent events, each `data` field holding one JSON-RPC message. type: string example: > event: message data: {"jsonrpc":"2.0","id":3,"result":{"content":[{"type":"text","text":"{\"operations\":[{\"operationID\":\"listBranches\",\"method\":\"GET\",\"path\":\"/organizations/{organizationID}/projects/{projectID}/branches\",\"summary\":\"List all branches\",\"callTool\":\"call_read_operation\"}]}"}],"isError":false}} '202': description: Notification or response accepted; no body is returned '400': description: >- Malformed message, unsupported `MCP-Protocol-Version`, or an `Accept` header missing one of the required media types '401': description: Missing or invalid credentials headers: WWW-Authenticate: description: >- Bearer challenge pointing at the protected resource metadata, per RFC 9728. schema: type: string example: >- Bearer resource_metadata="https://api.xata.tech/.well-known/oauth-protected-resource/mcp" '413': description: Request body larger than 4 MiB '415': description: '`Content-Type` is not `application/json`' '500': description: Internal server error security: - apiKey: [] - oidc: [] components: schemas: JSONRPCMessage: description: > A JSON-RPC 2.0 message. A request carries `id` and `method` and is answered with a response; a notification carries `method` without `id` and is not. The `method` and `params` values are defined by the MCP specification. type: object properties: jsonrpc: description: JSON-RPC protocol version. Always `2.0`. type: string enum: - '2.0' id: description: >- Request identifier, echoed on the response. Omitted for notifications. oneOf: - type: string - type: integer method: description: MCP method, such as `initialize`, `tools/list`, or `tools/call`. type: string params: description: Method parameters as defined by the MCP specification. type: object additionalProperties: true required: - jsonrpc - method JSONRPCResponse: description: A JSON-RPC 2.0 response. Exactly one of `result` or `error` is present. type: object properties: jsonrpc: description: JSON-RPC protocol version. Always `2.0`. type: string enum: - '2.0' id: description: Identifier of the request this responds to. oneOf: - type: string - type: integer result: description: Method result as defined by the MCP specification. type: object additionalProperties: true error: $ref: '#/components/schemas/JSONRPCError' required: - jsonrpc - id JSONRPCError: description: >- A JSON-RPC 2.0 error. Failures inside a tool are reported in the tool result with `isError`, not here. type: object properties: code: description: JSON-RPC error code. type: integer message: description: Short description of the error. type: string data: description: Additional error detail. required: - code - message securitySchemes: apiKey: type: apiKey in: header name: Authorization description: 'API key authentication using Bearer token format: Bearer ' oidc: type: openIdConnect openIdConnectUrl: https://auth.xata.io/realms/xata/.well-known/openid-configuration ````