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Connect Claude, Cursor and Codex

The relay lets your cloud MCP client reach Jack Runtime on your computer. Keep that computer awake and the Runtime running while using the connector.

Before you connect

Open the Jack desktop app, sign in and finish account setup. Use a Jack plan that includes the relay; Free accounts cannot connect. Have the Runtime running with the jack command available.

Connect the Runtime first

Run this on the computer the client should reach:

jack relay login

Open the device sign-in page, enter the code printed by the command and sign in. Use this same Jack account when authorizing the connector. If another Runtime is registered, the command asks before replacing it.

https://auth.jackforwork.com/device

jack relay status

Continue when the state is online. Login stores the credential; the running Runtime maintains the connection. The desktop app also offers relay connection in Settings on Pro.

Add the connector in claude.ai

These claude.ai option names were verified on 22 October 2026.

https://relay.jackforwork.com/mcp
  1. Open Settings › Connectors › Add › Add custom connector.
  2. Name the connector Jack and enter the URL above.
  3. Keep Authentication: Sign in now (Detected).
  4. Keep OAuth client: Use Claude’s published identity (Detected).
  5. Leave request headers empty.
  6. Select Add, sign in to Jack with the same account used for jack relay login, and approve access.

Use Claude’s published identity uses Client ID Metadata Documents (CIMD). Register automatically uses dynamic client registration, which Jack does not support. Use your own OAuth client is not needed. Leave request headers empty.

Cursor and Codex

For a cloud MCP connection in Cursor or Codex, use the same relay URL and the client’s own OAuth support to sign in to Jack and approve access. Connect the Runtime first and check that it is online. The client must support CIMD; dynamic client registration is not supported.

Menu paths and configuration syntax for Cursor and Codex are not documented here because they have not been verified.

Troubleshooting

Sign-in needed

Finish the connector’s Jack sign-in and approval. A missing or invalid connector token receives 401. If jack relay status shows logged_out or login_required, run jack relay login again on the Runtime’s computer.

Plan required

A Free account cannot use the relay. Choose a plan that includes it; 402 plan_required means your account does not yet have access.

Account setup not finished

For onboarding_required, open the Jack desktop app, sign in and finish account setup, then retry the connector.

Runtime offline

Keep the computer awake and the Runtime running, then check jack relay status for online. A stopped Runtime reports stopped locally; the relay returns 503 runtime_unreachable. Jack in the browser shows that Jack on your computer is not reachable.