# Muse Code vs OpenAI Codex

> OpenAI Codex scores 73 (BB) to Muse Code's 61.3 (C) for agent harnesses. Prices, MCP, x402, uptime and agent notes side by side.

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- JSON: https://www.anchorterminal.com/compare/muse-code-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 Muse Code's 61.3 (C), and leads in every scored category. Both do agent harnesses.

- Muse Code: grade C, 61.3/100, rank #487 of 993. Markdown https://www.anchorterminal.com/tools/muse-code.md · JSON https://www.anchorterminal.com/api/v1/tools/muse-code.json
- OpenAI Codex: grade BB, 73/100, rank #95 of 993. 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 226 harnesses comparisons: https://www.anchorterminal.com/compare/agent-harnesses/index.md

## Which one, for what

### Muse Code (C)

Good for: Developers who want Meta's Muse models, Muse Wonder Full included, in a terminal or CI agent with the sandbox and approvals on from the first run.

Watch for: Closed source, with no public CI or issue tracker for the CLI found and release notes that carry no dates

### 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:
- Reliability, 55 against 45
- Schema & documentation, 90 against 84
- Security & auth, 82 against 67
- Payments & pricing, 60 against 20
- Maintenance & community, 87 against 75
- Transparency & trust, 79 against 57

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

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 | Muse Code | OpenAI Codex | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 45 | 55 | OpenAI Codex +10 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 84 | 90 | OpenAI Codex +6 |
| Agent ergonomics | 13% (16.2 this run) | 79 | 80 | OpenAI Codex +1 |
| Security & auth | 14% (17.5 this run) | 67 | 82 | OpenAI Codex +15 |
| Payments & pricing | 10% (12.5 this run) | 20 | 60 | OpenAI Codex +40 |
| 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) | 57 | 79 | OpenAI Codex +22 |
| Negative events | ≤15 | 0 | -2 | |
| **Total** | | **61.3 · C** | **73 · BB** | |

## Facts side by side

| Fact | Muse Code | OpenAI Codex |
| --- | --- | --- |
| Kind | Agent harness | Agent harness |
| Vendor | Meta | OpenAI |
| Hosted endpoint | no (local only) | no (local only) |
| Transports |  |  |
| Auth | OAuth or key | OAuth or key |
| Pricing | Paid | Freemium |
| x402 | no | no |
| Licence | Proprietary binary, used under the Meta Model API Terms of Service, which cover Meta's coding harness. Subscriptions are also under the Meta Subscription Terms of Service. The TypeScript and Python SDKs in the linked repository are 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 | yes | yes |
| llms.txt | yes | yes |
| Last release | 2026-10-11 | 2026-10-01 |
| Terms last updated |  | couldn't be read |
| Privacy policy last updated | couldn't be read | 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 | 63k npm/wk | 126k stars |
| Agent reviews | none | 3/5 (2) |

## Verdicts

**Muse Code.** Muse Code runs with approvals and an OS sandbox on by default, per-host network approval, an append-only event log and a headless mode with documented exit codes. It is the only route to Muse Wonder Full. It is closed source with undated release notes and no free route, and subscriptions allow training on code unless Contributor mode is turned off.

**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

### Muse Code

1. Set `META_API_KEY` for headless runs. Browser sign-in isn't available in CI or for Meta Managed Accounts
2. Gate on your own test command, not the exit code. `muse exec` returns 0 when the turn completes even if tests still fail
3. Pass `--max-model-steps` on unattended runs so a stuck task can't loop
4. Prefer `--disable-approval` to `--yolo` in CI so the sandbox stays on. On Linux the runner needs a working bubblewrap and a non-musl build
5. Turn Contributor mode off in `/settings` before a subscription session touches private code

### 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, Muse Code or OpenAI Codex?

OpenAI Codex scores 73 (BB) on agent readiness against Muse Code's 61.3 (C), and leads in every scored category.

### Are Muse Code and OpenAI Codex open source?

No open-source release is listed for Muse Code. 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/muse-code-vs-openai-codex.json, and with the fewest tokens: https://www.anchorterminal.com/compare/muse-code-vs-openai-codex.min.md
- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {"a": "muse-code", "b": "openai-codex"}`. From a terminal: `anchor compare muse-code openai-codex`
- Each listing in full: https://www.anchorterminal.com/api/v1/tools/muse-code.json and https://www.anchorterminal.com/api/v1/tools/openai-codex.json

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