What it does

Codex is OpenAI's coding agent. The site presents it as a way to hand off real engineering work, including building features, refactors, migrations and routine pull requests, which the agent carries through to completion using OpenAI's coding models. Codex in ChatGPT is described as a command center for running several agents at once. Built-in worktrees and cloud environments let agents work in parallel across projects. Teams can use Skills to teach Codex their standards and workflows, and can schedule it to pick up recurring background work such as issue triage, alert monitoring and CI/CD. The same agent is offered in ChatGPT, in an editor extension and as a command-line tool, all connected through one ChatGPT account. The site also says Codex improves quality across a team through more thorough designs, testing and code review.

Capabilities

Works on features, refactors, migrations and pull requests from start to finish
Built-in worktrees and cloud environments for running agents in parallel
Skills that teach Codex a team's standards and workflows
Scheduled background work such as issue triage and alert monitoring
Available in ChatGPT, an IDE extension and a CLI under one ChatGPT account

When to use it

Delegating a feature, refactor or migration to an agent and reviewing the result
Running several coding tasks at once across different projects
Putting recurring chores such as issue triage or CI/CD follow-up on a schedule
Working from the terminal or an editor with the same agent you use in ChatGPT