Codex CLI vs Gemini CLI
Codex CLI (CLI / terminal agent, Included with ChatGPT plans) vs Gemini CLI (CLI / terminal agent, Free (Flash) + Google AI Pro): pricing, models, open-source status, benchmarks, and best use cases. See which AI coding agent is right for your workflow.
Codex CLI
Gemini CLI
| Comparison | Codex CLI | Gemini CLI |
|---|---|---|
| Category | CLI / terminal agent | CLI / terminal agent |
| Type | Terminal agent | Terminal agent |
| Vendor | OpenAI | |
| Pricing | Included with ChatGPT plans | Free (Flash) + Google AI Pro |
| Open source | Yes | Yes |
| Models | GPT-5.5, GPT-5.3 Codex, o-series reasoning | Gemini 3.1 Flash, Gemini 3.1 Pro |
| Benchmarks | Terminal-Bench: 82.7% | Not published |
| Best for | OpenAI ecosystem users, parallel task execution, open-source terminal workflows | Google ecosystem users, long-context tasks, low-cost experimentation on Flash |
Codex CLI is open source and best for openai ecosystem users, parallel task execution, open-source terminal workflows. OpenAI's open-source terminal coding agent. Supports parallel tasks and routes to GPT-5.5 and Codex models. Included with ChatGPT subscriptions; can also run on API keys.
Gemini CLI is open source and best for google ecosystem users, long-context tasks, low-cost experimentation on flash. Google's open-source terminal agent for Gemini models. Up to 1M-token context on Pro models. Free tier is generous for Flash; Pro models need a paid Google AI or API plan.
Both tools are part of the 2026 AI coding agent landscape. The right choice depends on whether you need a CLI / terminal agent or a CLI / terminal agent, your budget, and which models you prefer. See the full list of coding agents on our coding agents page to compare more options.