The provided document details how OpenAI utilizes its Codex system across various engineering teams, including Security, Frontend, and Infrastructure, to expedite numerous development tasks. Engineers use Codex daily to accelerate processes such as understanding complex codebases, executing large-scale refactoring and migration efforts, and improving performance by identifying and optimizing slow code paths. The system is also employed to enhance test coverage, increase overall development velocity by scaffolding new features, and help engineers maintain focus amidst fragmented schedules. Additionally, the document outlines several best practices for prompting Codex, such as starting with an implementation plan using "Ask Mode" and structuring prompts like a Github issue, to maximize its effectiveness