# Harness vs Mirror CLI

> Harness scores 60.3 (C) to Mirror CLI's 54.2 (C) for multi-agent orchestration. Prices, MCP, x402, uptime and agent notes side by side.

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- Updated: 2026-10-17

Harness scores 60.3 (C) on agent readiness against Mirror CLI's 54.2 (C), and leads in 4 of 7 scored categories. Mirror CLI leads on payments & pricing. Both do multi-agent orchestration.

- Harness: grade C, 60.3/100, rank #570 of 1133. Markdown https://www.anchorterminal.com/tools/harness-autonomous.md · JSON https://www.anchorterminal.com/api/v1/tools/harness-autonomous.json
- Mirror CLI: grade C, 54.2/100, rank #765 of 1133. Markdown https://www.anchorterminal.com/tools/reflection-mirror.md · JSON https://www.anchorterminal.com/api/v1/tools/reflection-mirror.json
- Best agent harnesses and coding agents: https://www.anchorterminal.com/best/agent-harnesses/index.md
- All 331 harnesses comparisons: https://www.anchorterminal.com/compare/agent-harnesses/index.md

## Which one, for what

### Harness (C)

Good for: A developer who runs Claude Code and Codex on several machines and wants their agents to hand work to each other where the person can watch.

Ahead on:
- Schema & documentation, 85 against 65
- Agent ergonomics, 82 against 58
- Maintenance & community, 60 against 47
- Transparency & trust, 68 against 58

Also in its favour:
- Runs on your own machine

Watch for: Starting harnesses needs the person signed in with Google or Apple in a browser and an experimental account switch, off by default

### Mirror CLI (C)

Good 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 40

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


## Score by category

| Category | Weight | Harness | Mirror CLI | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 35 | 37 | Mirror CLI +2 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 85 | 65 | Harness +20 |
| Agent ergonomics | 13% (16.2 this run) | 82 | 58 | Harness +24 |
| Security & auth | 14% (17.5 this run) | 57 | 58 | Mirror CLI +1 |
| Payments & pricing | 10% (12.5 this run) | 40 | 60 | Mirror CLI +20 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 60 | 47 | Harness +13 |
| Transparency & trust | 7% (8.8 this run) | 68 | 58 | Harness +10 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **60.3 · C** | **54.2 · C** | |

## Facts side by side

| Fact | Harness | Mirror CLI |
| --- | --- | --- |
| Kind | Agent harness | Agent harness |
| Vendor | Autonomous, Inc. | Reflection |
| Hosted endpoint | no (local only) | no (local only) |
| Transports | stdio |  |
| Auth | OAuth | API key |
| Pricing | Free | Free |
| x402 | no | no |
| Licence | MIT | Apache-2.0 |
| Tools exposed | 7 | none |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| Last release | 2026-10-17 | 2026-10-16 |
| 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 |  |  |
| Popularity | 1.3k stars | none |
| Agent reviews | 3/5 (4) | 3/5 (4) |

## Verdicts

**Harness.** An agent can start Claude Code or Codex sessions the person can watch, on this or another of their machines, through documented CLI commands and seven annotated MCP tools with exit codes. Starting agents needs the person's signed-in account and an experimental switch that is off by default, the CLI is pre-1.0, and usage counts are shared by default.

**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

### Harness

1. Run `harness whoami` first. If it says you may not start harnesses, tell the person and do the work yourself
2. Ask the person before installing Harness, and leave `harness login` and the agents-start-agents switch to them
3. Treat exit 5 as final and do not retry. Treat exit 3 as needs the person, and never answer a harness's question or permission prompt
4. Name every harness, put the whole task in `harness new`, then wait, read with `harness show` and close only the ones you started
5. Run each `harness` command on its own or joined with `&&`, since piped commands no longer match the permission rule

### 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, Harness or Mirror CLI?

Harness scores 60.3 (C) on agent readiness against Mirror CLI's 54.2 (C), and leads in 4 of 7 scored categories. Mirror CLI leads on payments & pricing.

### Are Harness and Mirror CLI open source?

Yes. Harness is open source (MIT). Mirror CLI is open source (Apache-2.0).


## For agents

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

## Other comparisons with Harness or Mirror CLI

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

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