Changing editor state used to be pasted straight into the message text, spending the user message's native budget and polluting history replay. Each turn now freezes structured additionalContext fragments instead (ide_context, open_tabs, workspace_context, referenced_files_<index>, terminal_context_<index>), so every fragment enjoys its own native budget and the request text stays pristine. The service sniffs the selected CLI once per child process via app-server generate-json-schema --experimental to learn whether turn/start accepts additionalContext, and re-sniffs after a runtime replacement; discovery never creates a thread or turn and cancels leave it early. Older CLIs get the official desktop text envelope with UTF-8 text-element byte ranges shifted accordingly, and history replay strips that envelope so users only ever see their own request. Cover the flow with schema-probe, fallback, cancellation and daemon tests on the bridge side plus context-budget, payload-copy and display sanitizer tests on the Java side; document the contract in docs/codex/app-server.md.
npm i -g @openai/codex
or brew install --cask codex
Codex CLI is a coding agent from OpenAI that runs locally on your computer.
If you want Codex in your code editor (VS Code, Cursor, Windsurf), install in your IDE
If you are looking for the cloud-based agent from OpenAI, Codex Web, go to chatgpt.com/codex
Quickstart
Installing and running Codex CLI
Install globally with your preferred package manager. If you use npm:
npm install -g @openai/codex
Alternatively, if you use Homebrew:
brew install --cask codex
Then simply run codex to get started:
codex
If you're running into upgrade issues with Homebrew, see the FAQ entry on brew upgrade codex.
You can also go to the latest GitHub Release and download the appropriate binary for your platform.
Each GitHub Release contains many executables, but in practice, you likely want one of these:
- macOS
- Apple Silicon/arm64:
codex-aarch64-apple-darwin.tar.gz - x86_64 (older Mac hardware):
codex-x86_64-apple-darwin.tar.gz
- Apple Silicon/arm64:
- Linux
- x86_64:
codex-x86_64-unknown-linux-musl.tar.gz - arm64:
codex-aarch64-unknown-linux-musl.tar.gz
- x86_64:
Each archive contains a single entry with the platform baked into the name (e.g., codex-x86_64-unknown-linux-musl), so you likely want to rename it to codex after extracting it.
Using Codex with your ChatGPT plan
Run codex and select Sign in with ChatGPT. We recommend signing into your ChatGPT account to use Codex as part of your Plus, Pro, Team, Edu, or Enterprise plan. Learn more about what's included in your ChatGPT plan.
You can also use Codex with an API key, but this requires additional setup. If you previously used an API key for usage-based billing, see the migration steps. If you're having trouble with login, please comment on this issue.
Model Context Protocol (MCP)
Codex can access MCP servers. To configure them, refer to the config docs.
Configuration
Codex CLI supports a rich set of configuration options, with preferences stored in ~/.codex/config.toml. For full configuration options, see Configuration.
Execpolicy
See the Execpolicy quickstart to set up rules that govern what commands Codex can execute.
Docs & FAQ
- Getting started
- Configuration
- Sandbox & approvals
- Execpolicy quickstart
- Authentication
- Automating Codex
- Advanced
- Zero data retention (ZDR)
- Contributing
- Install & build
- FAQ
- Open source fund
License
This repository is licensed under the Apache-2.0 License.

