# Pi vs Muse Code

> Pi scores 68.4 (B) to Muse Code's 61.3 (C) for agent harnesses. Prices, MCP, x402, uptime and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/earendil-pi-vs-muse-code
- Markdown: https://www.anchorterminal.com/compare/earendil-pi-vs-muse-code.md (~2,650 tokens)
- Slim: https://www.anchorterminal.com/compare/earendil-pi-vs-muse-code.min.md (~630 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/earendil-pi-vs-muse-code.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

Pi scores 68.4 (B) on agent readiness against Muse Code's 61.3 (C), and leads in 4 of 7 scored categories. Muse Code leads on security & auth. Both do agent harnesses.

- Pi: grade B, 68.4/100, rank #219 of 993. Markdown https://www.anchorterminal.com/tools/earendil-pi.md · JSON https://www.anchorterminal.com/api/v1/tools/earendil-pi.json
- 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
- 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

### Pi (B)

Good for: Developers and pipelines that want a small, scriptable coding agent they can extend in TypeScript and drive over JSONL or RPC, inside their own container.

Ahead on:
- Reliability, 75 against 45
- Payments & pricing, 60 against 20
- Maintenance & community, 87 against 75
- Transparency & trust, 64 against 57

Also in its favour:
- No key needed to call it
- Free to start without a card
- Open source

Watch for: No permission system or sandbox. Tool calls run with the user's rights and without an approval prompt

### 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.

Ahead on:
- Security & auth, 67 against 61

Also in its favour:
- No incidents deducted, where Pi loses 4 points for them

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


## Score by category

| Category | Weight | Pi | Muse Code | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 75 | 45 | Pi +30 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 84 | 84 | even |
| Agent ergonomics | 13% (16.2 this run) | 76 | 79 | Muse Code +3 |
| Security & auth | 14% (17.5 this run) | 61 | 67 | Muse Code +6 |
| Payments & pricing | 10% (12.5 this run) | 60 | 20 | Pi +40 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 87 | 75 | Pi +12 |
| Transparency & trust | 7% (8.8 this run) | 64 | 57 | Pi +7 |
| Negative events | ≤15 | -4 | 0 | |
| **Total** | | **68.4 · B** | **61.3 · C** | |

## Facts side by side

| Fact | Pi | Muse Code |
| --- | --- | --- |
| Kind | Agent harness | Agent harness |
| Vendor | Earendil | Meta |
| Hosted endpoint | no (local only) | no (local only) |
| Transports |  |  |
| Auth | None | OAuth or key |
| Pricing | Free | Paid |
| x402 | no | no |
| Licence | MIT | 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. |
| Read-only variant documented | no | yes |
| llms.txt | no | yes |
| Last release | 2026-10-07 | 2026-10-11 |
| Terms last updated | no document linked |  |
| Privacy policy last updated | no document linked | couldn't be read |
| Customer content may train models |  |  |
| Terms restrict automated access |  |  |
| Terms restrict benchmarking |  |  |
| Terms or service can change without notice |  |  |
| Arbitration or class-action waiver |  |  |
| Popularity | 113k stars, 5.2M npm/wk | 63k npm/wk |

## Verdicts

**Pi.** Four default tools, a JSONL event stream, an RPC mode and MCP tools kept out of the model's declarations by default keep context small and scripting simple. Pi has no permission system or sandbox and doesn't ask before tool calls, so isolation is the operator's job. Version 1.0.0 is dated 1 October 2026.

**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.

## Before you call either

### Pi

1. Run Pi inside a container or VM for unattended work. It has no sandbox and doesn't ask before running shell commands
2. Use `pi --mode json` and wait for `agent_settled`. A failed response doesn't set a nonzero exit code in JSON mode
3. Split the JSONL stream on LF only. Node's `readline` also splits on U+2028 and U+2029, which are valid inside JSON strings
4. Pass `--no-approve` or `--approve` in scripts to make the project trust decision explicit
5. Set `PI_TELEMETRY=0` and `PI_SKIP_VERSION_CHECK=1`, or `PI_OFFLINE=1`, to stop the default requests to pi.dev

### 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

## Questions

### Which is better for AI agents, Pi or Muse Code?

Pi scores 68.4 (B) on agent readiness against Muse Code's 61.3 (C), and leads in 4 of 7 scored categories. Muse Code leads on security & auth.

### Are Pi and Muse Code open source?

Pi is open source (MIT). No open-source release is listed for Muse Code.


## For agents

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

## Other comparisons with Pi or Muse Code

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