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OpenAI Codex CLI
OpenAI Codex CLI
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Gemini CLI
Gemini CLI

OpenAI Codex CLI vs Gemini CLI — Which AI Agent Is Better?

An in-depth comparison of OpenAI Codex CLI and Gemini CLI across output quality, autonomy, reliability, speed, value, and ease of use. Vote for your favorite.

Community Vote

Pick a winner in each category — you can change your vote anytime.

Output Quality
Writes correct, production-ready code and answers
Autonomy
Completes multi-step tasks end-to-end without hand-holding
Reliability
Consistent results — doesn't go off the rails or break
Speed
Fast responses and quick task turnaround
Value
What you get for what you pay
Ease of Use
From install to first useful result with minimal friction
Codex
Gemini CLI
Category
Coding Agent
Coding Agent
Pricing
Included with ChatGPT plans / API
Generous free tier / Gemini API
Open Source
Yes
Yes
Best For
ChatGPT subscribers who want a capable terminal agent at no extra cost
Developers who want frontier-agent capability with huge context at zero cost
Key Features
Sandboxed command execution, Configurable approval modes, Multi-file editing
1M-token context window, Generous free quota, MCP server support

Verdict: Codex or Gemini CLI?

Updated 2026-06-12

Choose OpenAI Codex CLI if you are chatGPT subscribers who want a capable terminal agent at no extra cost. Choose Gemini CLI if you are developers who want frontier-agent capability with huge context at zero cost.

In our editorial scoring, OpenAI Codex CLI leads in 3 of six categories (output quality, autonomy and reliability), while Gemini CLI leads in 2 (speed and value). On price, OpenAI Codex CLI runs included with chatgpt plans / api and is open source; Gemini CLI runs generous free tier / gemini api and is open source.

Where Codex falls short
  • Best models are tied to the OpenAI ecosystem
  • Younger as a CLI tool than Aider — fewer battle-tested workflows
Full Codex review →
Where Gemini CLI falls short
  • Output quality on complex edits typically lands a notch below Claude Code and Codex
  • Free-tier usage may be used for product improvement — check data settings for sensitive code
Full Gemini CLI review →

In-Depth Comparison

OpenAI Codex CLI Overview

Codex CLI is OpenAI's open-source coding agent for the terminal. It edits files, runs commands in a sandbox with configurable approval modes, and can hand longer tasks off to Codex cloud to run in the background. Usage is included with ChatGPT Plus/Pro plans, making it the default choice for developers already in the OpenAI ecosystem.

Gemini CLI Overview

Gemini CLI is Google's open-source AI agent for the terminal. Its standout traits are a 1M-token context window that can hold entire codebases and a free tier generous enough for real daily work with just a personal Google account. It supports MCP servers, Google Search grounding, and shell command execution in an agentic loop.

Score Breakdown

Output Quality
9.0
vs
8.0
Autonomy
8.5
vs
7.5
Reliability
8.0
vs
7.5
Speed
8.0
vs
8.5
Value
7.5
vs
9.5
Ease of Use
8.0
vs
8.0

Features

Codex
  • Sandboxed command execution
  • Configurable approval modes
  • Multi-file editing
  • Cloud task handoff
  • GitHub integration
  • Scriptable automation
Gemini CLI
  • 1M-token context window
  • Generous free quota
  • MCP server support
  • Google Search grounding
  • Shell command execution
  • Open source (Apache 2.0)

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