Cursor MCP Not Working: Server Connected but No Tools

How to fix it

Try these in order — the most common fix is first.

1. 1. Toggle and restart

   Copy steps
   1. Settings > Tools & MCP: turn the server off and on
   2. Fully restart Cursor
   Did this fix it? Yes No

2. 2. Read the logs

   Copy steps
   1. Open View > Output and choose the MCP channel
   2. Look for crashes or schema errors
   Did this fix it? Yes No

3. 3. Fix tool schemas

   1. Avoid nullable property types; follow the MCP spec for inputSchema
   Did this fix it? Yes No

4. 4. Check your mcp.json

   Copy steps
   1. Verify command, args and environment variables in .cursor/mcp.json or the global file
   2. Run the server command manually in a terminal
   Did this fix it? Yes No

Symptoms

MCP shows connected with 0 tools, tools missing for the agent, or old tool descriptions after edits.

Why it happens

• Stale tool list until restart (known to staff)
• Invalid or nullable tool input schemas rejected by validation
• Server process crashing and restarting
• Regression in specific versions

This guide also covers

• cursor mcp not working
• cursor mcp 0 tools
• cursor mcp server not showing

Other Cursor errors

• Cursor Usage Limit Reached
• Cursor Rate Limit Exceeded
• Cursor Agent Not Working
• Cursor High Load Error (ERROR_RESOURCE_EXHAUSTED)
• Cursor Keeps Reconnecting or Connection Failed
• Cursor Extensions Not Working or Not Found
• Cursor Slow, High CPU or Memory Usage
• Can't Use Cursor Auto After Included Usage Is Gone