Codex

Codex is a cloud-based software engineering agent from OpenAI that can work on many tasks in parallel. Powered by codex-1, a version of OpenAI o3 optimized for software engineering, Codex can perform tasks such as writing features, answering questions about your codebase, fixing bugs, and proposing pull requests for review. Each task runs in its own cloud sandbox environment, preloaded with your repository. Codex operates entirely within a secure, isolated container in the cloud with disabled internet access during task execution, limiting interaction solely to the code explicitly provided via GitHub repositories. The agent provides verifiable evidence of its actions through citations of terminal logs and test outputs, allowing you to trace each step taken during task completion. Users can review results, request further revisions, open GitHub pull requests, or directly integrate changes into their local environment. Codex can be guided by AGENTS.md files placed within repositories for project-specific instructions and best practices.