Codex Desktop

Codex Desktop adds MCP servers from its settings, and shares ~/.codex/config.toml with the command line.

Before you start

You need a Reduck account, and a paired browser if you want scripts to run on your own Chrome. Both are in the quick start.

Install the Codex version Reduck is tested against:

npm i -g @openai/codex@0.141.0

Pin that version. Later releases have broken the connection to Reduck.

Add the server

Open Settings → MCP servers and click ＋ Add server.

Select Streamable HTTP, set the name to Reduck and the URL to https://mcp.reduck.ai, then save.

Restart Codex.

Confirm it is connected

Run /mcp in a session. Reduck is listed, and the first call opens a browser to sign in to your Reduck account.

Settings worth changing

Codex asks for approval before each tool call, which interrupts a script mid-run. To let Reduck run unattended, set the approval mode for the server in ~/.codex/config.toml:

[mcp_servers.reduck]
url = "https://mcp.reduck.ai"
default_tools_approval_mode = "auto"

This applies to Reduck alone; every other server keeps asking.

To lift approvals for one session instead, start Codex with codex --full-auto — sandbox workspace-write, approval on-failure. That choice lasts only as long as the session.

If it does not appear

• The account is on the free tier. Codex Pro is required for MCP servers.
• The server was added as stdio rather than Streamable HTTP. A stdio server expects a command to launch, and Reduck is a URL.
• Codex was not restarted after the server was added.