Cursor

Cursor installs MCP servers from a link. Click the button, confirm in Cursor, then sign in to OnlyX.

One click

Add OnlyX to Cursor

Opens Cursor’s install dialog for the OnlyX server. Cursor must be installed.

The button is Cursor’s install link. config is the base64 of {"url":"https://mcp.onlyx.ai/mcp"}:

cursor://anysphere.cursor-deeplink/mcp/install?name=OnlyX&config=eyJ1cmwiOiJodHRwczovL21jcC5vbmx5eC5haS9tY3AifQ%3D%3D

If your browser does not open Cursor, use the web version of the same link, which shows a page with an Open in Cursor button:

https://cursor.com/en/install-mcp?name=OnlyX&config=eyJ1cmwiOiJodHRwczovL21jcC5vbmx5eC5haS9tY3AifQ%3D%3D

Confirm the install

Cursor opens its MCP install dialog showing OnlyX and https://mcp.onlyx.ai/mcp. Click Install.

In Cursor Settings → MCP (called Tools & Integrations in some versions), OnlyX shows that it needs a login. Click Connect (or Login). Your browser opens OnlyX: sign in, choose the workspace, and click Approve.

Use it

In the chat’s Agent mode, ask: “Which OnlyX workspace am I connected to?” Cursor asks before it runs each tool unless you allow it.

Configure by hand

Add the server to ~/.cursor/mcp.json (all projects) or .cursor/mcp.json in a project.

OAuth
API key

~/.cursor/mcp.json

{
  "mcpServers": {
    "onlyx": {
      "url": "https://mcp.onlyx.ai/mcp"
    }
  }
}

Cursor registers itself with OnlyX automatically and asks you to sign in the first time.

~/.cursor/mcp.json

{
  "mcpServers": {
    "onlyx": {
      "url": "https://mcp.onlyx.ai/mcp",
      "headers": {
        "Authorization": "Bearer ${env:ONLYX_API_KEY}"
      }
    }
  }
}

Set ONLYX_API_KEY in the environment Cursor starts from (for example your shell profile), and restart Cursor. Never commit a key in a project’s .cursor/mcp.json; the ${env:...} form keeps it out of the file. A Read only key makes Cursor read-only in OnlyX.

Troubleshooting

Problem	Fix
Clicking the button does nothing	Cursor is not installed, or your browser blocked the `cursor://` link. Use the `https://cursor.com/en/install-mcp` link, or configure by hand.
OnlyX shows a red dot or “needs login”	Click Connect next to it in Cursor Settings → MCP and sign in again.
”Unauthorized” with an API key	The key is wrong, revoked or expired, or `ONLYX_API_KEY` is not set where Cursor runs.
The tools list is empty	Toggle the OnlyX server off and on in Cursor Settings → MCP.

Using OnlyX with Claude and other assistants: recipes.
Tools: the full tool list.

MCP server

Connect your assistant

Reference

One click

Add OnlyX to Cursor

Configure by hand

Troubleshooting

Next

​One click

Add OnlyX to Cursor

​Configure by hand

​Troubleshooting

​Next

One click

Configure by hand

Troubleshooting

Next