Codex CLIvsZero
Generated from the two spec rows. Green marks the better value where a spec has a clear direction. Everything else is just different.
Codex CLI
OpenAI · Terminal agent
#1OSSMCP
Panel
7.12 spec wins
- Reliability
- 7.3
- Usefulness
- 7.0
- Cost
- 6.8
- Longevity
- 7.2
“Apache-2.0, so you can read every line except the one that lets you pick a model that is not OpenAI's.”
Zero
Gitlawb · Terminal agent
#6OSSMCP
Panel
7.03 spec wins
- Reliability
- 6.7
- Usefulness
- 7.0
- Cost
- 8.2
- Longevity
- 6.2
“It accepts image input in a terminal, a sentence that would have ended a career in 2019.”
Spec by spec
| Spec | Codex CLI | Zero |
|---|---|---|
| Architecture | ||
| Category | Terminal agent | Terminal agent |
| Runs | local | local, sandbox |
| Platforms | macos, linux, windows | macos, linux, windows |
| Context window | not documented | not documented |
| Protocols | ||
| MCP client | Yes | Yes |
| MCP server | No | Yes |
| Capabilities | ||
| Runs terminal commands | Yes | Yes |
| Multi-file edits | Yes | Yes |
| Git operations | Yes | Yes |
| Browser control | NoThe shared Codex codebase carries a browser-use configuration with Chrome DevTools Protocol access, but OpenAI's documentation states browser is not available in the Codex CLI or the IDE extension; it runs in ChatGPT on the web and in the desktop app. The CLI's --search flag adds live web search only. | YesBrowser and terminal control helpers ship with the npm and release builds; source builds need those helper binaries on PATH or configured in local-control settings. |
| Sandboxed execution | Yes | NoZero ships a native Linux sandbox helper using seccomp rather than Docker; source builds must build the `zero-linux-sandbox` helper separately. |
| Multi-agent orchestration | Yes | Yes |
| Headless / CI mode | Yes | Yes`zero exec` returns exit codes and has a documented GitHub Action recipe. |
| Models | ||
| Backbone | OpenAI GPT-5.x, GPT-5.x-Codex | OpenAI, Anthropic, Gemini, Groq, OpenRouter, DeepSeek, Mistral, xAI, Qwen, Kimi, GitHub Models, Fireworks, MiniMax, Ollama, LM Studio |
| Bring your own model | Yes | Yes |
| Local models | Yes | Yes |
| Cost | ||
| Pricing model | mixed | byok |
| Starts at | $8/mo | $0/mo |
| Free tier | Yes | Yes |
| Bring your own key | Yes | Yes |
| Openness | ||
| Open source | Yes | Yes |
| License | Apache-2.0 | MIT |
| GitHub stars | 127,563 | 1,688 |
Which one would each critic pick
| Critic | Codex CLI | Zero | Pick |
|---|---|---|---|
| El Juez | — | — | not enough reviews |
| El Amigo | 8.0 | 7.3 | Codex CLI — If you already pay for ChatGPT, this is the terminal agent you have and it is a good one; open source, MCP, headless, and pointed at OpenAI until you configure it otherwise. |
| El Crítico | 7.0 | 6.8 | Codex CLI — A sandbox mode you choose once is the only barrier between the agent and your shell, the free tier is a taste, and the defaults point at one vendor. |
| El Profesor | 6.3 | 7.3 | Zero — Sessions can be resumed or forked, which makes a continuation a controlled variable, and the headless mode emits text, JSON or stream-JSON rather than prose only. |
| La Inversora | 8.3 | 5.5 | Codex CLI — A lab's terminal agent bundled into a $20 subscription with 121,000 stars on the repo; the distribution is ChatGPT, and that is the whole thesis. |
| La Jefa | 7.3 | 6.8 | Codex CLI — Business at $20 a seat with SAML SSO and no default training, Enterprise for SCIM and audit logs; if the org is on ChatGPT already, this is a line item, not a project. |
| El Hacker | 5.8 | 8.5 | Zero — MIT, twenty-five providers with Ollama and LM Studio among them, and it works as an MCP server as well as a client, so my tools go both ways. |
Picks are derived from each critic's own scores. Humans vote on matchups on the duels page.