Skip to main content

Configure Cursor

Cursor supports MCP servers through its native settings UI as of Cursor 0.45+.

Add the server (UI)​

  1. Cursor → Settings → MCP.
  2. Click + Add new MCP server.
  3. Fill in:
    • Name: onesource
    • Type: command
    • Command: npx -y @one-source/mcp@latest
    • Environment variables: ONESOURCE_API_KEY=sk_…
  4. Click Save.

Add the server (config file)​

Alternatively, edit ~/.cursor/mcp.json for a global config that applies to every project, or .cursor/mcp.json in a project root for a per-project config (create if absent):

{
  "mcpServers": {
    "onesource": {
      "command": "npx",
      "args": ["-y", "@one-source/mcp@latest"],
      "env": { "ONESOURCE_API_KEY": "sk_…" }
    }
  }
}

Verify​

Open Composer or Chat and ask: "Call 1s_setup_check." The tool card should report Status: Configured (API key).

Troubleshooting​

  • Cursor doesn't see the server: hit the refresh button on the MCP settings page or restart the app. New env vars require a restart.
  • 403 / wrong key: see Claude Code; same shadowing pattern applies.
  • Some onesource tools missing in Composer: Cursor caps active tools across all MCP servers at ~40. If you have multiple MCPs configured, disable the ones you aren't using on the MCP settings page.
  • Invalid JSON: a stray comma or bracket in mcp.json silently prevents the server from loading. Validate with a linter.

Next​