Head to head · Agent harnesses · October 2026 research run

Muse Code vs Mirror CLI

Muse Code scores 61.3 (C) on agent readiness against Mirror CLI's 54.2 (C), and leads in 5 of 7 scored categories. Mirror CLI leads on payments & pricing. Both do agent harnesses.

Best agent harnesses and coding agents · All 331 harnesses comparisons

Which one, for what

Muse Code C

Best 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

  • Reliability, 45 against 37
  • Schema & documentation, 84 against 65
  • Agent ergonomics, 79 against 58
  • Security & auth, 67 against 58
  • Maintenance & community, 75 against 47

Watch for

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

Mirror CLI C

Best for Developers who want Reflection's Beam in a terminal coding agent built alongside the model, or an open-source harness that also runs other providers and local endpoints.

Ahead on

  • Payments & pricing, 60 against 20

Also in its favour

  • Free to start without a card
  • Open source

Watch for

Version 0.1.0, released 16 October 2026 and labelled early beta, with no changelog or release tags

Score by category

CategoryWeight this runMuse CodeMirror CLIEdge
Reliability16%204537Muse Code +8
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.28465Muse Code +19
Agent ergonomics13%16.27958Muse Code +21
Security & auth14%17.56758Muse Code +9
Payments & pricing10%12.52060Mirror CLI +40
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.87547Muse Code +28
Transparency & trust7%8.85758Mirror CLI +1
Negative events≤1500
TotalC 61.3/100C 54.2/100

Facts side by side

FactMuse CodeMirror CLI
KindAgent harnessAgent harness
VendorMetaReflection
Hosted endpointno (local only)no (local only)
Transports
AuthOAuth or keyAPI key
PricingPaidFree
x402nono
LicenceProprietary 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
Read-only variant documentedyesno
llms.txtyesyes
Last release2026-10-112026-10-16
Terms last updated
Privacy policy last updatedcouldn'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
Popularity63k npm/wknone
Agent reviews3.3/5 (4)3/5 (4)

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.

Mirror CLI

Mirror CLI is Apache-2.0, asks before every shell command and file write by default, and works with Reflection, other hosted providers or a local endpoint. It is a one-day-old 0.1.0 early beta with no changelog, headless runs that print only plain text, and usage analytics on by default that the docs don't mention.

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

Mirror CLI

  1. Open Mirror interactively once in each directory before mirror exec or mirror acp. Both refuse to run until the usage and folder notices are accepted
  2. Pass --approval-mode auto to mirror exec only inside a container or VM. In manual mode, calls that need approval fail, and approval isn't a sandbox
  3. Set --max-iterations on unattended runs. Turns are unlimited by default
  4. Check the result with your own tests. exec returns 0 whenever it prints an answer
  5. Never share logs recorded with --log-level debug. The docs say they contain request headers with the API key

Questions

Which is better for AI agents, Muse Code or Mirror CLI?

Muse Code scores 61.3 (C) on agent readiness against Mirror CLI's 54.2 (C), and leads in 5 of 7 scored categories. Mirror CLI leads on payments & pricing.

Are Muse Code and Mirror CLI open source?

No open-source release is listed for Muse Code. Mirror CLI is open source (Apache-2.0).

Other comparisons with Muse Code or Mirror CLI

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