---
title: "Send an MCP JSON-RPC request"
method: POST
path: "/mcp"
tags: ["MCP Server"]
---

# Send an MCP JSON-RPC request

`POST /mcp`

## Request

- Base URL: `https://api.oneschema.co`
- URL: `https://api.oneschema.co/mcp`
- Auth: API key in header `X-API-KEY`

Send a JSON-RPC 2.0 request to the OneSchema MCP server. MCP clients use
this endpoint to initialize the connection, list available tools and
resources, call read-only tools, and read resources.

Notifications that do not require a response return `202 Accepted` with
an empty body. Requests return a JSON-RPC response object.

## Request body

- JsonRpcRequest
  - `jsonrpc` '2.0', required: JSON-RPC protocol version
  - `id` union: Request identifier. Omit for notifications.
    - string
    - integer
  - `method` string, required: JSON-RPC method, such as `initialize`, `tools/list`, `tools/call`, `resources/list`, or `resources/read`.
  - `params` JsonRpcParams

## Response `200`

JSON-RPC response

- JsonRpcResponse
  - `jsonrpc` '2.0', required
  - `id` union: The request identifier.
    - string
    - integer
  - `result` JsonRpcResult
  - `error` JsonRpcError
    - `code` integer, required
    - `message` string, required
    - `data` unknown

## Other responses

- `202`: Notification accepted; no response body
- `401`: Unauthorized (missing or invalid API key)
- `403`: Forbidden
- `422`: Request could not be processed

---

[API](https://skmtc.dev/oneschema/apis/mcp-server.md) - [All operations](https://skmtc.dev/oneschema/apis/mcp-server/llms.txt) - [OpenAPI document](https://skmtc.dev/oneschema/apis/mcp-server/revisions/7784bf4a8e26?raw)