Beta
Agent · Assistive

Codex CLI

Codex is OpenAI's command-line coding agent that runs GPT models locally against your repository with a lightweight REPL-style loop.

by OpenAI·Open harness·Apache-2.0·Launched Apr 2025
Capability
no benchmarks
GitHub stars
74.6k
Harness
ReAct loop
Built-in tools
Environments
1
Terminal

No public benchmark submissions · yet

Codex CLI has not published benchmark scores on SWE-bench Verified, GAIA, OSWorld or τ-bench. Check the GitHub repo or vendor site for the latest · we track new submissions daily.

Awaiting snapshot history · 1 days recorded

Awaiting star history · run scripts/fetch-github-stars.ts to populate.

Brain · Harness · Tools · Environment

Brains
Which LLM powers it
gpt-5o3
Harness
The loop pattern
ReAct loop
Tools
How it acts on the world
Built-in
Environments
Where it lives
Terminal

Pulled from the dataset · updated daily

What is Codex CLI?

Codex is OpenAI's command-line coding agent that runs GPT models locally against your repository with a lightweight REPL-style loop.

What model powers Codex CLI?

Codex CLI runs on gpt-5 and o3. It uses a react loop pattern with built-in tools.

Is Codex CLI open-source?

The harness is open under Apache-2.0 but Codex CLI depends on gpt-5 / o3, which are closed models. You bring your own API key.

How popular is Codex CLI?

Codex CLI has 74,591 stars on GitHub across 404 contributors.

Brains used

GitHub stats

Repoopenai/codex
Stars74,591
Contributors404
Created2025-04-13
Last commit2026-04-11
How we score
Methodology

Composite capability · momentum formula · data sources.

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