Codex in ChatGPT

Codex is OpenAI's coding agent, accessible through the ChatGPT web app, a terminal CLI, a desktop app for Windows and macOS, and IDE integrations such as VS Code, Cursor, and Windsurf. It is built to complete real software engineering work end to end: pull requests, refactors, code reviews, migrations, and new features, rather than just suggesting code snippets inline. A notable part of the design is parallel execution. Codex can run multiple agent sessions across projects at once using isolated worktrees and cloud environments, and it supports "Skills" that let a team teach it their coding standards and workflows so results stay consistent across tasks. It can also be scheduled to handle recurring work like issue triage or CI/CD monitoring without a human kicking off each run. Access is tied to a ChatGPT account: Plus, Pro, Business, Edu, and Enterprise plans can use it, and there is also API key authentication for programmatic use. The CLI portion of the project is open source under the Apache-2.0 license and has a large GitHub following. It is aimed at professional developers and engineering teams looking to automate routine coding work, not at people writing their first program, since it assumes familiarity with git workflows, pull requests, and codebases.