Cursor – Open Context Docs

Cursor has no Open Context catalog listing, so you add the hosted server by URL. It’s one entry in a config file and a browser sign-in.

Claude and ChatGPT do have catalog listings, and those paths are shorter — see Claude and ChatGPT.

Before you start

An Open Context account at opnctx.ai with a few things already saved. Retrieval only returns what’s in your Library.
A Cursor build that supports MCP and remote HTTP servers — check Settings → Tools & MCP.

Where the config goes

Cursor reads an mcpServers block from a JSON file. Use one of these:

Scope	Path
Global (all workspaces)	macOS / Linux: `~/.cursor/mcp.json` — Windows: `%USERPROFILE%\.cursor\mcp.json`
Project (this repo only)	`<repo-root>/.cursor/mcp.json`

If the same server name appears in both, the project entry wins.

Edit the file directly, or use Settings → Tools & MCP to add a server — the UI writes the same JSON.

Setup

Cursor connects over streamable HTTP and runs OAuth in your browser. No local process, and no API key in the config.

Add the server

Under mcpServers, point an entry at the hosted URL:

{
  "mcpServers": {
    "open-context": {
      "url": "https://mcp.opnctx.ai"
    }
  }
}

Use any stable key you like instead of open-context — that name only labels the server in Cursor’s UI.

Restart Cursor

Save the file, quit Cursor completely, and launch it again. A window reload often isn’t enough for a new MCP server to register.

On first connect, Cursor opens your browser. Sign in at opnctx.ai and approve access. Cursor stores the tokens.

Check the tools

Open the MCP panel and confirm Open Context tools are listed — get_profile, search_library, stash_content, and the rest. Then try an Agent prompt that depends on something you saved.

See MCP tools reference for the full list.

Troubleshooting

Tools disappear, or you get auth errors. Consent expired or was revoked. Disconnect the server in Tools & MCP, remove the stale entry if one is left behind, re-add https://mcp.opnctx.ai, and sign in again.

Open Context tools are missing but others work. Cursor caps how many tools it loads across all MCP servers at once. Disable tools you don’t use on noisier servers so there’s room.

You can’t run a browser sign-in. The hosted endpoint also accepts an API key as a bearer token — see Any MCP client. Don’t commit that key.

For the protocol and auth background, see How it works.

ChatGPT Any MCP client