How to use the ClearRun MCP server

The ClearRun MCP server is the @clearrun/mcp package (1.2.0). It adds four tools to MCP apps like Claude Desktop, Claude Code, Cursor and VS Code: clearrun_score, clearrun_evaluate, clearrun_chat and clearrun_verify. A verified free account can create one developer key.

Last updated November 9, 2026

Add the server

Add this to your app's MCP config, with your own key in place of YOUR_CLEARRUN_API_KEY. Don't commit a real key.

{
  "mcpServers": {
    "clearrun": {
      "command": "npx",
      "args": ["-y", "@clearrun/mcp"],
      "env": {
        "CLEARRUN_API_KEY": "YOUR_CLEARRUN_API_KEY"
      }
    }
  }
}

In Cursor the file is .cursor/mcp.json. File names for other apps are in the MCP readme.

The server sends every request to the hosted API. It has no mock mode. Node.js 18 or newer is required.

The tools

ClearRun MCP tools
Tool	What it does
`clearrun_score`	Scores text you already have
`clearrun_evaluate`	Scores an answer with the question that produced it
`clearrun_chat`	Gets an answer from a model and scores it
`clearrun_verify`	Looks up a past verdict id. Does not score

Ask in plain words, for example: "Use clearrun_score on this answer." None of the tools check facts.

If the API returns 403, code API_ACCESS_REQUIRED means the key is not a free developer key. A verified free account can create one.