Claude Design for Codex

A Codex plugin for working with and exporting live Claude Design projects and prototypes.

Anthropic's Claude Design OAuth client uses a manual-code callback that is not compatible with Codex's standard localhost MCP callback. This plugin bridges that flow locally and forwards authenticated traffic to Anthropic's remote Claude Design MCP server.

Install from Codex

In Codex, add this GitHub repository as a plugin marketplace:

thomast8/codex-claude-design-plugin

Then install Claude Design from the marketplace. The equivalent CLI commands are:

codex plugin marketplace add thomast8/codex-claude-design-plugin
codex plugin add claude-design@claude-design

Start a new task after installation so Codex loads the plugin.

Connector behaviour

When Claude Design is explicitly named, the plugin keeps the request on the Claude Design connector. Verbs such as “open”, “read”, “download”, and “export” do not route the task to a browser. Browser tooling is used only when requested or for visual QA of the connector's short-lived preview URL.

The bridge adds two local tools to Anthropic's MCP surface:

• download_file_to_local downloads one project file as exact raw bytes, including PNG, JPEG, GIF, WebP, fonts, PDFs, and other binary assets.
• export_project_to_local creates a complete standalone local directory and a .claude-design-export.json manifest containing source etags, byte counts, content types, and SHA-256 hashes.

Both tools require a new absolute destination under the user's home or temporary directory and refuse to overwrite existing paths.

First-use authentication

The first Claude Design request opens a local browser helper. The helper keeps the OAuth verifier on your machine while you:

1. Select Authorise with Claude.
2. Approve Claude Design in the new Claude tab.
3. Copy the short-lived CODE#STATE value Claude displays.
4. Return to the local helper tab and paste it there.

The helper exchanges the code directly with Anthropic, stores the resulting credentials with owner-only permissions, and lets the pending Codex request continue. Do not paste the code into chat.

Credentials are stored outside the plugin at:

~/.config/codex-claude-design/credentials.json

To inspect or reset authentication without locating Codex's plugin cache:

npm exec --yes \
  --package=github:thomast8/codex-claude-design-plugin \
  -- claude-design-codex status

npm exec --yes \
  --package=github:thomast8/codex-claude-design-plugin \
  -- claude-design-codex logout

Security notes

• The browser helper binds only to 127.0.0.1, uses an unpredictable local form token, and shuts down after authentication or ten minutes.
• OAuth access and refresh tokens are never printed.
• The access token is passed to the MCP bridge through a child-process environment variable, not a command-line argument.
• The remote endpoint is Anthropic's https://api.anthropic.com/v1/design/mcp.
• This is an independent community plugin and is not affiliated with or endorsed by Anthropic or OpenAI.

The bridge pins mcp-remote to version 0.1.37. Its OAuth implementation is adapted from erdnj/claude-design-mcp at commit 5e50b691df5259668cf80fcd41766d4da17a80ce under the MIT licence. See THIRD_PARTY_NOTICES.md.

Documentation status: generated by Codex on 30 July 2026 and not yet human-reviewed.