# Muse Code vs Prime Agent

> Muse Code and Prime Agent score within a point of each other for agent harnesses, 61.3 and 60.5 out of 100. Prices, MCP, x402, uptime and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/muse-code-vs-prime-agent
- Markdown: https://www.anchorterminal.com/compare/muse-code-vs-prime-agent.md (~2,800 tokens)
- Slim: https://www.anchorterminal.com/compare/muse-code-vs-prime-agent.min.md (~680 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/muse-code-vs-prime-agent.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

Muse Code and Prime Agent score within a point of each other on agent readiness, 61.3 (C) and 60.5 (C). Prime Agent leads on reliability, payments & pricing and transparency & trust. 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
- Prime Agent: grade C, 60.5/100, rank #526 of 993. Markdown https://www.anchorterminal.com/tools/prime-agent.md · JSON https://www.anchorterminal.com/api/v1/tools/prime-agent.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.

Ahead on:
- Schema & documentation, 84 against 42
- Agent ergonomics, 79 against 73
- Security & auth, 67 against 50

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

### Prime Agent (C)

Good for: Long-running research and coding work where one model drives subagents, schedules and goals from code, and where the owner can isolate the machine.

Ahead on:
- Reliability, 65 against 45
- Payments & pricing, 60 against 20
- 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 approval prompts and no sandbox. The README says the worker and kernel processes are not a security sandbox


## Score by category

| Category | Weight | Muse Code | Prime Agent | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 45 | 65 | Prime Agent +20 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 84 | 42 | Muse Code +42 |
| Agent ergonomics | 13% (16.2 this run) | 79 | 73 | Muse Code +6 |
| Security & auth | 14% (17.5 this run) | 67 | 50 | Muse Code +17 |
| Payments & pricing | 10% (12.5 this run) | 20 | 60 | Prime Agent +40 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 75 | 79 | Prime Agent +4 |
| Transparency & trust | 7% (8.8 this run) | 57 | 64 | Prime Agent +7 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **61.3 · C** | **60.5 · C** | |

## Facts side by side

| Fact | Muse Code | Prime Agent |
| --- | --- | --- |
| Kind | Agent harness | Agent harness |
| Vendor | Meta | Prime Intellect |
| Hosted endpoint | no (local only) | no (local only) |
| Transports |  |  |
| Auth | OAuth or key | None |
| Pricing | Paid | Free |
| 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. | MIT |
| Read-only variant documented | yes | no |
| llms.txt | yes | no |
| Last release | 2026-10-11 | 2026-10-07 |
| Terms last updated |  | no date given |
| Privacy policy last updated | couldn't be read | no date given |
| Customer content may train models |  | not found in the text |
| Terms restrict automated access |  | yes |
| Terms restrict benchmarking |  | yes |
| Terms or service can change without notice |  | yes |
| Arbitration or class-action waiver |  | yes |
| Popularity | 63k npm/wk | 22k stars |

## 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.

**Prime Agent.** Budgets for turns, tokens and time bound an autonomous run, and sessions survive a closed terminal through a supervising daemon. Model-written Python and shell commands run with the user's rights, with no approval step and no sandbox, and the Rust build on the main branch ships only as nightly betas.

## 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

### Prime Agent

1. Run it in a disposable clone, container or VM. It executes model-written Python and shell commands with the user's rights and asks nothing first
2. Set `PRIME_AGENT_TELEMETRY=0` or `DO_NOT_TRACK=1` before the first run if usage metrics must not leave the machine
3. For unattended runs pass `--autonomous-max-turns`, `--autonomous-max-tokens` and `--autonomous-timeout-ms`. Reaching a limit does not mean the task succeeded
4. Headless use is `-p` with `--mode json` per the argument parser. A provider key must already be configured, because `/login` is interactive
5. The `-t/--tools`, `-nt/--no-tools` and `-nbt/--no-builtin-tools` flags were removed and now fail as unknown options

## Questions

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

Muse Code and Prime Agent score within a point of each other on agent readiness, 61.3 (C) and 60.5 (C). Prime Agent leads on reliability, payments & pricing and transparency & trust.

### Are Muse Code and Prime Agent open source?

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


## For agents

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

## Other comparisons with Muse Code or Prime Agent

- [Agent Zero vs Muse Code](https://www.anchorterminal.com/compare/agent-zero-vs-muse-code.md)
- [Agent Zero vs Prime Agent](https://www.anchorterminal.com/compare/agent-zero-vs-prime-agent.md)
- [Aider vs Muse Code](https://www.anchorterminal.com/compare/aider-vs-muse-code.md)
- [Aider vs Prime Agent](https://www.anchorterminal.com/compare/aider-vs-prime-agent.md)
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