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Coding agent (CLI) · OpenAI

Codex CLI

OpenAI's open-source, Rust-based terminal coding agent. Signs in with a ChatGPT plan or an API key, runs commands under a sandbox with approval controls, and supports MCP, subagents and codex exec for scripts.

Reviewed by the Termdex team · facts checked 2026-10-28 against 8 vendor sources · how we check

Official site

Codex CLI review

Codex CLI is OpenAI's open-source terminal coding agent, written in Rust. It runs on macOS, Windows and Linux under the Apache-2.0 licence. We read the vendor's pages and repository in October 2026. We did not run an independent test.

Who it is for

ChatGPT subscribers and OpenAI API users who want an open-source CLI coding agent with a sandbox. It is a weaker fit if you need non-OpenAI or local models officially documented.

What stands out

You sign in with a ChatGPT plan or an OpenAI API key. Commands run under a sandbox with approval controls, and a permissions command shows the active sandbox.

The docs cover codex exec for CI and scripts, local and remote MCP servers, and subagents. A search option is also documented. Install is a curl script, npm, Homebrew, or a PowerShell installer on Windows.

Models are OpenAI's. The pricing page lists GPT-6.1 Sol, GPT-6.1 Terra and GPT-6 Luna. With an API key, the models you can use follow what the key can access.

Price and licence

The licence is Apache 2.0, and we read the LICENSE file in the repository. We saw no extra terms. That is open source.

The CLI is free, and model cost comes from your OpenAI account. On the pricing page, seen 28 October 2026, Codex is included in ChatGPT Free ($0), Go ($8 a month) and Plus ($20 a month). Pro starts at $100 a month. Business is $20 per user monthly on annual billing, or $25 monthly. Enterprise and Edu are by contact. Usage limits apply. We did not verify the individual Pro tiers.

An API key is billed at standard API rates.

Where it falls short

Alternatives

Compare more tools in terminal coding agents. OpenCode is MIT-licensed and works with many providers. Gemini CLI is also Apache-2.0.

Facts: platforms, price and licence

platforms
macOSWindowsLinuxREADME gives a native PowerShell installer for Windows, and OpenAI's Windows docs say Codex runs natively with a Windows sandbox (WSL optional). The repo file docs/install.md still lists 'Windows 11 via WSL2' and macOS 12+/Ubuntu 20.04+/Debian 10+, which looks out of date.
price
FreeThe CLI itself is free (Apache-2.0). Model cost comes from your OpenAI account (seen 2026-10-28): sign in with a ChatGPT plan, where Codex is included in Free ($0), Go ($8/month), Plus ($20/month), Pro (from $100/month; $100, $200 or $500 tiers), Business ($20/user/month annual, $25 monthly) and Enterprise/Edu (contact sales), with usage limits; or use an OpenAI API key billed at standard API rates (no cloud features).
source
Open sourceLicence: Apache-2.0
github
openai/codex 131.3k stars, seen 2026-10-28

Codex CLI features

✓ documented · – absent or not in its feature list · ? not verified

Codex CLI strengths

  • Apache-2.0 with a very active repo (release published 2026-10-27)
  • Two sign-in routes: ChatGPT plan (including a $0 Free tier listed on the pricing page) or an API key
  • Documented codex exec for CI/scripts, local and remote MCP servers, subagents, and a permissions command showing the active sandbox
  • Native Windows sandbox documented, plus standalone installers for macOS, Linux and Windows

Codex CLI weak points

  • Codex cloud features require ChatGPT sign-in; API-key use is limited and excludes cloud features such as GitHub code review
  • Tied to OpenAI models in the official docs; local-model support was not found in OpenAI's own pages
  • Plan usage limits are per 5-hour/weekly window and depend on model and task size
  • Repo docs/install.md contradicts the main docs on native Windows support

Who Codex CLI is for

best for
ChatGPT subscribers or OpenAI API users who want an open-source, sandboxed terminal agent.
look elsewhere if
Anyone who needs to run it on non-OpenAI or local models and wants that officially documented.

Compare Codex CLI

Lists that include Codex CLI

Sources and what we could not verify

Checked 2026-10-28. Prices and features change; the vendor's page is the authority.

Not verified