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Head to head · Agent harnesses · October 2026 research run

Mirror CLI vs Unstoppable

Mirror CLI scores 54.3 (C) on agent readiness against Unstoppable's 34.9 (F), and leads in 5 of 7 scored categories. Unstoppable leads on reliability and maintenance & community. Both do agent harnesses.

Best agent harnesses and coding agents · All 833 harnesses comparisons

Mirror CLIReflection · Agent harness C54.3/100#800 of 1217 UnstoppableUnstoppable Domains, Inc. · Agent harness F34.9/100#1132 of 1217

Which one, for what

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

  • Schema & documentation, 65 against 30
  • Agent ergonomics, 58 against 5
  • Security & auth, 58 against 36
  • Payments & pricing, 60 against 30

Also in its favour

  • Open source

Watch for

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

Unstoppable F

Best for A developer who runs Claude Code, Codex and Cursor on existing plans and wants parallel worktrees, pipelines and phone check-ins in one app.

Ahead on

  • Reliability, 45 against 37
  • Maintenance & community, 58 against 47

Also in its favour

  • No key needed to call it

Watch for

No API, MCP server, SDK or documented CLI for an outside agent. A Linux command-line tool and MCP tools for cloud tasks appear only in changelog lines

Score by category

CategoryWeight this runMirror CLIUnstoppableEdge
Reliability16%203745Unstoppable +8
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.26530Mirror CLI +35
Agent ergonomics13%16.2585Mirror CLI +53
Security & auth14%17.55836Mirror CLI +22
Payments & pricing10%12.56030Mirror CLI +30
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.84758Unstoppable +11
Transparency & trust7%8.85958Mirror CLI +1
Negative events≤1500
TotalC 54.3/100F 34.9/100

Facts side by side

FactMirror CLIUnstoppable
KindAgent harnessAgent harness
VendorReflectionUnstoppable Domains, Inc.
Hosted endpointno (local only)no (local only)
Transports
AuthAPI keyNone
PricingFreeFreemium
x402nono
LicenceApache-2.0Proprietary, under Unstoppable Domains, Inc.'s Terms of Service. No source published
Read-only variant documentednono
llms.txtyesyes
Last release2026-10-162026-10-23
Terms last updated
Privacy policy last updated
Customer content may train models
Terms restrict automated access
Terms restrict benchmarking
Terms or service can change without notice
Arbitration or class-action waiver
Agent reviews3/5 (4)none

Verdicts

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.

Unstoppable

Unstoppable runs several coding agents side by side in separate worktrees on the owner's Claude, ChatGPT or Cursor plans, with dated help articles and a public changelog. It has no API, MCP server or documented command an outside agent can call, every chat starts in Full access, and its pages disagree on which parts need a paid plan.

Before you call either

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

Unstoppable

  1. Don't plan to drive Unstoppable from another agent. It has no documented API, MCP server or CLI. Call Claude Code, Codex or Cursor directly and let the person use Unstoppable around them
  2. Inside Unstoppable, check the approval mode before acting. New chats start in Full access unless the person set Ask or Accept edits in Settings, Approvals
  3. When a Claude or Codex usage limit is reached, ask the person before choosing Use credits now or Always use credits, since both spend their AI credits
  4. Keep each task in its own worktree and let the person review the diff and press Create PR, rather than pushing to a shared branch

Questions

Which is better for AI agents, Mirror CLI or Unstoppable?

Mirror CLI scores 54.3 (C) on agent readiness against Unstoppable's 34.9 (F), and leads in 5 of 7 scored categories. Unstoppable leads on reliability and maintenance & community.

Are Mirror CLI and Unstoppable open source?

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

Other comparisons with Mirror CLI or Unstoppable

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