Cursor

Cursor supports MCP servers through its settings UI or a .cursor/mcp.json file. See the MCP server reference for the full tool list and response shapes.

Install the server

Make sure the plumb binary is on your PATH. If you installed via cargo install plumb-cli, it should already be available. If you built from source, confirm with which plumb or where plumb on Windows.

Configure via .cursor/mcp.json

Create .cursor/mcp.json in your project root:

{
  "mcpServers": {
    "plumb": {
      "command": "plumb",
      "args": ["mcp"]
    }
  }
}

Alternatively, open Cursor Settings → Features → MCP Servers → Add Server, then enter the command plumb with arguments mcp.

For a source checkout:

{
  "mcpServers": {
    "plumb": {
      "command": "cargo",
      "args": ["run", "--quiet", "-p", "plumb-cli", "--", "mcp"]
    }
  }
}

Verify the connection

After saving the config, restart Cursor or reload the MCP connection from Settings → Features → MCP Servers. The server should appear as connected with its tools listed.

Test the transport:

Use plumb’s echo tool to send “hello”.

Lint a page

Ask Cursor’s agent:

Use plumb to lint https://example.com

The agent calls lint_url and returns the violation summary. Request detail: "full" for the complete JSON output.

Common issues

PATH resolution, working directory, large responses, and tool approval prompts apply to every agent integration. See Common issues for the consolidated list.

The Cursor-specific note: macOS GUI Cursor often launches with a minimal PATH, so an absolute binary path in .cursor/mcp.json is the most reliable fix. Cursor also prompts to approve MCP tool calls on first use — accept the prompt to allow Plumb tools.

See also

• MCP server reference — tool list, response shapes, resource URIs.
• Configuration — plumb.toml reference.
• Install — binary installation options.