How Do I Connect Cursor to an MCP Server?

What Cursor can do with an MCP server

Yes, Cursor supports MCP: remote servers over HTTP with OAuth, and local servers it launches itself. Once connected, the agent can use whatever tools that server offers. Connected to a knowledge base like Hjarni, Cursor can:

Search

Find relevant notes by keyword or topic before it writes code

Read

Pull in the full content of an architecture note, ADR, or runbook

Create

Save a new note straight from the editor after a session

Organize

Tag notes, move them between folders, add links

Follow instructions

Read your custom AI instructions and apply them to every response

The specific capabilities depend on the MCP server. Each server exposes its own set of tools.

In practice that looks like: ask Cursor why the auth layer uses custom middleware and it reads the ADR instead of guessing; hit the same Sidekiq retry bug six months later and it walks your old runbook; finish a tricky refactor and have it write the lesson down for next time.

What you need

• Cursor on a paid plan. MCP is listed under Pro and above (Pro, Pro+, Ultra, and the Teams tiers), not the free Hobby plan. There is no extra flag to enable beyond that.
• The MCP server you want to connect. Either a remote URL like https://hjarni.com/mcp, or a local command Cursor can launch.

The config file: two scopes

Cursor reads MCP servers from mcp.json, and the same format works in two places:

• ~/.cursor/mcp.json is global. The server is available in every project you open. Right for a knowledge base, since your notes are not repo-specific.
• .cursor/mcp.json inside a repo is project-scoped. The server only exists in that project. Right for project-specific tooling, and the file can be committed so teammates get it too.

Both take a single mcpServers object with one entry per server.

Remote servers (OAuth)

A remote MCP server that supports OAuth needs only its URL: no API key, no token in the file.

{
  "mcpServers": {
    "hjarni": {
      "url": "https://hjarni.com/mcp"
    }
  }
}

Save the file and restart Cursor. On first use, Cursor opens the server's OAuth page in your browser. Sign in and authorize, once. The connection persists across sessions after that.

If a server only offers bearer-token auth, you can pass the token in a headers block, but prefer OAuth whenever the server supports it, so no credential lives in a file. The Cursor bearer token fix covers that setup and the 401s that come with it.

Local servers

For a local MCP server, Cursor launches the process itself. Give it a command instead of a URL:

{
  "mcpServers": {
    "your-server": {
      "command": "npx",
      "args": ["-y", "your-mcp-server"]
    }
  }
}

Remote and local entries can live side by side in the same mcpServers object.

Verifying the connection

Open Cursor Settings > MCP: the server should be listed with its tools. Then open the agent and ask it to use one. For example, if you connected Hjarni:

"Search Hjarni for our deploy runbook."

Cursor should call the server's search tool and answer from your notes. If you see the tool call in the response, the connection is working.

Troubleshooting

Try it with Hjarni

Hjarni is a knowledge base with a built-in MCP server. Connect it to Cursor and your agent can read the context that is not in the repo (architecture decisions, runbooks, conventions) and write new notes back. Stop re-explaining your codebase.

The MCP server URL is https://hjarni.com/mcp. Add the entry above to ~/.cursor/mcp.json, restart, sign in. Two minutes. For the full setup with use cases, see Hjarni for Cursor.

Connect your notes