Understand a codebase
Trace unfamiliar files, explain how parts connect, and identify where a change belongs.
AI Tool Blog Codex product overview
Meet Codex, OpenAI’s coding agent.
Codex works with the context of a real project to help you understand code, make focused changes, run development tools, and review the result. Start from an official OpenAI entry point, then use our guides when you need a structured next step.
External buttons open official OpenAI pages. Availability and installation requirements can change, so confirm them on the linked page.
What Codex is for
A coding agent for the full development loop.
Codex is most useful when it has a clear goal, the right project context, and permission boundaries that match the task.
Make focused changes
Edit code and supporting files while keeping the requested outcome and repository rules in view.
Run and review
Use local tools, inspect diffs, and check the result before you decide what should ship.
Official screenshots
What Codex looks like
Five figures from OpenAI’s own Codex page: the three surfaces it lists under “The same agent everywhere you code” — Codex in ChatGPT, the IDE extension and the CLI — plus two of the capability shots the page uses for its own feature sections. They are OpenAI’s product graphics rather than generated output, because a coding agent’s output is a diff, not a picture.
Images © OpenAI, from the Codex product page
Learn with AI Tool Blog
Choose the path that matches your goal.
These are independent AI Tool Blog resources, not OpenAI documentation. Each collection uses its own article URLs and reading navigation.
Free Guides
Start using Codex with practical guidance
Follow approachable workflows for setup, first tasks, and everyday use without starting from API or automation details.
Go to Codex Free Guides Developer DocsBuild a reliable Codex development workflow
Go deeper into CLI setup, repository instructions, commands, permissions, review, and repeatable automation.
Go to Codex Developer DocsLatest Codex articles
Browse every published Codex article, from introductions to practical guides and developer documentation.
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Codex vs. ChatGPT: Which Should You Use?
Compare Codex and ChatGPT for coding: repository access, execution, output style, and best-fit tasks, so you can pick the right tool for each job.
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Codex app, CLI, IDE, or cloud: how to choose the right surface
Compare the Codex CLI, IDE extension, desktop app, and cloud tasks to match the right surface to your workflow, repository access, and review flow.
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Your First Low-Risk Coding Task with Codex: A Safe Walkthrough
Give Codex a small, reversible first task: read repo rules, request one bounded change, review the diff, run existing checks, and roll back cleanly if needed.
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How to Write Better Codex Prompts: A Practical Framework
Learn how to write Codex prompts with a clear outcome, relevant context, firm boundaries, and verifiable acceptance criteria, plus reusable examples.
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How to Review Codex Code Changes Before You Commit
Review Codex code changes before committing: separate old work from new edits, inspect risky diff patterns, run checks, and record unresolved issues.
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What Is Codex? Capabilities, Limits, and Ways to Use It
Learn how OpenAI Codex works, where you can use it, which tasks it handles well, and why permissions, tests, and human review still matter.
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Codex Beginner Tutorial: Complete Your First Safe Task
Follow a low-risk Codex workflow: choose a project, define constraints, review the diff, run real checks, and decide whether the result is ready.
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Install Codex CLI: Sign In and Run Your First Safe Task
Install Codex CLI from the official source, sign in from the right project directory, inspect permissions, run a safe first task, and review the diff.
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Codex AGENTS.md Guide: Layered Rules and Validation
Learn how Codex discovers and merges AGENTS.md files, organizes layered project rules, and verifies scope without override or truncation mistakes.
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Codex CLI Commands: Sessions, Review, and Automation
Find Codex CLI commands for login, sessions, review, automation, and slash controls, with practical guidance on directories, permissions, and dangerous flags.
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