What is grok-in-codex?

Grok in Codex is a plugin that lets you call Grok from inside the Codex coding assistant for tasks such as code reviews, delegated coding fixes, background investigations, and image or video generation. Codex remains in charge of the overall session, the plugin adds a small MCP server that talks to a local Grok command line tool through a shared companion process running on your machine. Once installed, it adds a set of tools Codex can call, including checking that Grok is set up and authenticated, delegating an investigation or fix that is allowed to write changes by default, running a structured read only review of a branch, tree, or pull request, running an adversarial review that challenges a design's assumptions, generating or editing images and short videos into local output folders, and checking on or canceling background jobs. It also ships a handful of skills that help Codex decide when to hand work off to Grok and how to write strong prompts for it. Using it requires Node.js 18.18 or later, the Grok CLI available on your system path and already logged in, and the GitHub CLI if you want to review pull requests directly. Installation is a couple of Codex plugin commands, either pulling the plugin from GitHub or pointing at a local copy of the repository, followed by starting a new Codex thread so the tools load. From there you can simply ask Codex in plain language to have Grok review a branch, investigate a flaky test, or generate a launch banner image, or call the underlying tools directly with specific options like running a background job or choosing a faster or deeper model. Delegated fix tasks default to being able to write changes automatically, with an option to force read only analysis or to isolate risky edits in a separate git worktree. There is a sibling plugin for people using Claude Code instead of Codex.