How to add ClearRun to Cursor

Steps

1. Create .cursor/mcp.json

   In your project. To use it in every project, use ~/.cursor/mcp.json instead.

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

2. Add your key

   Replace YOUR_CLEARRUN_API_KEY. If the project is shared, use the file in your home folder so the key stays out of the repo.

3. Check it is on

   Open Cursor's MCP settings and check that clearrun is listed and turned on.

4. Try it

   In the agent chat, ask: "Use clearrun_score on this answer:" and paste the answer.

The four tools

• clearrun_score: scores text you already have.
• clearrun_evaluate: scores an answer with the question that produced it.
• clearrun_chat: asks ClearRun for an answer and scores it.
• clearrun_verify: looks up a verdict id. No key, no credits.

Score and evaluate use credits. A chat turn costs at most 4 credits. None of the tools check facts.

If it does not work

• "No ClearRun API key is configured." The env block is missing or the key is empty.
• 403 API_ACCESS_REQUIRED. That key is not a free developer key. Create one on a verified free account, or score in the web app with Paste Check.
• Server not listed. Check that npx works in a terminal, then restart Cursor.