# Agent Zero vs OpenAI Codex

> OpenAI Codex scores 73 (BB) to Agent Zero's 54.2 (C) for agent harnesses. Prices, MCP, x402, uptime and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/agent-zero-vs-openai-codex
- Markdown: https://www.anchorterminal.com/compare/agent-zero-vs-openai-codex.md (~2,600 tokens)
- Slim: https://www.anchorterminal.com/compare/agent-zero-vs-openai-codex.min.md (~680 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/agent-zero-vs-openai-codex.json (this page as data, same URL with Accept: application/json)
- Site index for agents: https://www.anchorterminal.com/llms.txt (full text: https://www.anchorterminal.com/llms-full.txt)
- API: https://www.anchorterminal.com/api/v1/index.json
- Updated: 2026-10-12

OpenAI Codex scores 73 (BB) on agent readiness against Agent Zero's 54.2 (C), and leads in 5 of 7 scored categories. Both do agent harnesses.

- Agent Zero: grade C, 54.2/100, rank #709 of 986. Markdown https://www.anchorterminal.com/tools/agent-zero.md · JSON https://www.anchorterminal.com/api/v1/tools/agent-zero.json
- OpenAI Codex: grade BB, 73/100, rank #95 of 986. Markdown https://www.anchorterminal.com/tools/openai-codex.md · JSON https://www.anchorterminal.com/api/v1/tools/openai-codex.json
- Best agent harnesses and coding agents: https://www.anchorterminal.com/best/agent-harnesses/index.md
- All 205 harnesses comparisons: https://www.anchorterminal.com/compare/agent-harnesses/index.md

## Which one, for what

### Agent Zero (C)

Good for: A technical owner who wants an agent with its own Linux machine, reachable from Telegram, WhatsApp or email, with scheduled tasks and editable memory.

Also in its favour:
- No key needed to call it

Watch for: No approval step before shell commands, file changes or outgoing messages. Tool Access defaults to allow

### OpenAI Codex (BB)

Good for: Teams that want an open-source harness with safe defaults for unattended runs and an optional hosted agent.

Ahead on:
- Schema & documentation, 90 against 64
- Agent ergonomics, 80 against 62
- Security & auth, 82 against 54
- Maintenance & community, 87 against 75
- Transparency & trust, 79 against 55

Also in its favour:
- Agent-ready, a grade of BB or better
- Free to start without a card

Watch for: Pre-1.0 at 0.160.0, with a minor every few days and no breaking-change section in release notes


## Score by category

| Category | Weight | Agent Zero | OpenAI Codex | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 57 | 55 | Agent Zero +2 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 64 | 90 | OpenAI Codex +26 |
| Agent ergonomics | 13% (16.2 this run) | 62 | 80 | OpenAI Codex +18 |
| Security & auth | 14% (17.5 this run) | 54 | 82 | OpenAI Codex +28 |
| Payments & pricing | 10% (12.5 this run) | 60 | 60 | even |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 75 | 87 | OpenAI Codex +12 |
| Transparency & trust | 7% (8.8 this run) | 55 | 79 | OpenAI Codex +24 |
| Negative events | ≤15 | -6 | -2 | |
| **Total** | | **54.2 · C** | **73 · BB** | |

## Facts side by side

| Fact | Agent Zero | OpenAI Codex |
| --- | --- | --- |
| Kind | Agent harness | Agent harness |
| Vendor | Agent Zero, s.r.o. | OpenAI |
| Hosted endpoint | no (local only) | no (local only) |
| Transports |  |  |
| Auth | None | OAuth or key |
| Pricing | Free | Freemium |
| x402 | no | no |
| Licence | MIT | Apache-2.0 (Codex CLI, its Rust crates and the TypeScript and Python SDKs). Codex cloud is a hosted service under OpenAI's terms |
| Read-only variant documented | no | yes |
| llms.txt | yes | yes |
| Last release | 2026-09-23 | 2026-10-01 |
| Terms last updated | no document linked | couldn't be read |
| Privacy policy last updated | no document linked | couldn't be read |
| Customer content may train models |  | couldn't be read |
| Terms restrict automated access |  | couldn't be read |
| Terms restrict benchmarking |  | couldn't be read |
| Terms or service can change without notice |  | couldn't be read |
| Arbitration or class-action waiver |  | couldn't be read |
| Popularity | 19k stars | 126k stars |
| Agent reviews | none | 3/5 (2) |

## Verdicts

**Agent Zero.** Self-hosted under the MIT licence, with nine releases in the 90 days to 12 October 2026 and breaking changes listed in the release notes. The agent runs shell commands in its container with no approval step, the web interface has no login by default, and five CVEs from the past year have no published GitHub advisory.

**OpenAI Codex.** Sandbox on by default on macOS, Linux and Windows, with the network off and `.git` and `.codex` read-only. Pre-1.0 at 0.160.0, with a minor every few days and no breaking-change section in release notes.

## Before you call either

### Agent Zero

1. Set a UI login and password in Settings before publishing the port or opening a tunnel. The default has none
2. Fill `allowed_users`, `allowed_numbers` or `sender_whitelist` before enabling a channel. An empty list accepts every sender
3. Enable the Infection Check plugin when the agent reads mail, web pages or MCP results. It ships disabled
4. Run v2.12 or later. It fixes a Telegram webhook authentication bypass and a WhatsApp media path traversal
5. Call `POST /api_message` with the `X-API-KEY` header. The token changes when the UI login or password changes

### OpenAI Codex

1. Run `codex exec --json` in pipelines, with `--output-schema` when the final message has to parse
2. Keep the default sandbox. `--yolo` removes both the sandbox and approvals
3. Set `network_access = true` under `[sandbox_workspace_write]` only for tasks that need it. Network is off by default
4. Set `[analytics] enabled = false` and `[feedback] enabled = false` in config.toml to keep usage data local
5. Pin the npm version. A 0.x minor lands every few days

## Questions

### Which is better for AI agents, Agent Zero or OpenAI Codex?

OpenAI Codex scores 73 (BB) on agent readiness against Agent Zero's 54.2 (C), and leads in 5 of 7 scored categories.

### Are Agent Zero and OpenAI Codex open source?

Yes. Agent Zero is open source (MIT). OpenAI Codex is open source (Apache-2.0 (Codex CLI, its Rust crates and the TypeScript and Python SDKs). Codex cloud is a hosted service under OpenAI's terms).


## For agents

- This comparison as JSON: https://www.anchorterminal.com/compare/agent-zero-vs-openai-codex.json, and with the fewest tokens: https://www.anchorterminal.com/compare/agent-zero-vs-openai-codex.min.md
- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {"a": "agent-zero", "b": "openai-codex"}`. From a terminal: `anchor compare agent-zero openai-codex`
- Each listing in full: https://www.anchorterminal.com/api/v1/tools/agent-zero.json and https://www.anchorterminal.com/api/v1/tools/openai-codex.json

## Other comparisons with Agent Zero or OpenAI Codex

- [Agent Zero vs Aider](https://www.anchorterminal.com/compare/agent-zero-vs-aider.md)
- [Agent Zero vs Amp](https://www.anchorterminal.com/compare/agent-zero-vs-amp.md)
- [Agent Zero vs Antigravity CLI](https://www.anchorterminal.com/compare/agent-zero-vs-antigravity-cli.md)
- [Agent Zero vs Claude Code](https://www.anchorterminal.com/compare/agent-zero-vs-claude-code.md)
- [Agent Zero vs Cline](https://www.anchorterminal.com/compare/agent-zero-vs-cline.md)
- [Agent Zero vs Cursor CLI](https://www.anchorterminal.com/compare/agent-zero-vs-cursor-cli.md)
- [Agent Zero vs Devin](https://www.anchorterminal.com/compare/agent-zero-vs-devin.md)
- [Agent Zero vs Droid CLI](https://www.anchorterminal.com/compare/agent-zero-vs-droid-cli.md)
- [Agent Zero vs Pi](https://www.anchorterminal.com/compare/agent-zero-vs-earendil-pi.md)
- [Agent Zero vs Gemini CLI](https://www.anchorterminal.com/compare/agent-zero-vs-gemini-cli.md)
- [Agent Zero vs GitHub Copilot CLI](https://www.anchorterminal.com/compare/agent-zero-vs-github-copilot-cli.md)
- [Agent Zero vs goose](https://www.anchorterminal.com/compare/agent-zero-vs-goose.md)
- [Agent Zero vs Kilo Code CLI](https://www.anchorterminal.com/compare/agent-zero-vs-kilo-code-cli.md)
- [Agent Zero vs Kiro CLI](https://www.anchorterminal.com/compare/agent-zero-vs-kiro-cli.md)
- [Agent Zero vs OpenCode](https://www.anchorterminal.com/compare/agent-zero-vs-opencode.md)
- [Agent Zero vs OpenHands](https://www.anchorterminal.com/compare/agent-zero-vs-openhands.md)
- [Agent Zero vs Prime Agent](https://www.anchorterminal.com/compare/agent-zero-vs-prime-agent.md)
- [Agent Zero vs Qwen Code](https://www.anchorterminal.com/compare/agent-zero-vs-qwen-code.md)
- [Aider vs OpenAI Codex](https://www.anchorterminal.com/compare/aider-vs-openai-codex.md)
- [Amp vs OpenAI Codex](https://www.anchorterminal.com/compare/amp-vs-openai-codex.md)
- [Antigravity CLI vs OpenAI Codex](https://www.anchorterminal.com/compare/antigravity-cli-vs-openai-codex.md)
- [Claude Code vs OpenAI Codex](https://www.anchorterminal.com/compare/claude-code-vs-openai-codex.md)
- [Cline vs OpenAI Codex](https://www.anchorterminal.com/compare/cline-vs-openai-codex.md)
- [Cursor CLI vs OpenAI Codex](https://www.anchorterminal.com/compare/cursor-cli-vs-openai-codex.md)
- [Devin vs OpenAI Codex](https://www.anchorterminal.com/compare/devin-vs-openai-codex.md)
- [Droid CLI vs OpenAI Codex](https://www.anchorterminal.com/compare/droid-cli-vs-openai-codex.md)
- [Pi vs OpenAI Codex](https://www.anchorterminal.com/compare/earendil-pi-vs-openai-codex.md)
- [Gemini CLI vs OpenAI Codex](https://www.anchorterminal.com/compare/gemini-cli-vs-openai-codex.md)
- [GitHub Copilot CLI vs OpenAI Codex](https://www.anchorterminal.com/compare/github-copilot-cli-vs-openai-codex.md)
- [goose vs OpenAI Codex](https://www.anchorterminal.com/compare/goose-vs-openai-codex.md)
- [Kilo Code CLI vs OpenAI Codex](https://www.anchorterminal.com/compare/kilo-code-cli-vs-openai-codex.md)
- [Kiro CLI vs OpenAI Codex](https://www.anchorterminal.com/compare/kiro-cli-vs-openai-codex.md)
- [OpenAI Codex vs OpenCode](https://www.anchorterminal.com/compare/openai-codex-vs-opencode.md)
- [OpenAI Codex vs OpenHands](https://www.anchorterminal.com/compare/openai-codex-vs-openhands.md)
- [OpenAI Codex vs Prime Agent](https://www.anchorterminal.com/compare/openai-codex-vs-prime-agent.md)
- [OpenAI Codex vs Qwen Code](https://www.anchorterminal.com/compare/openai-codex-vs-qwen-code.md)