# Antigravity CLI vs Harness

> Harness scores 60.3 (C) to Antigravity CLI's 57.4 (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 Antigravity CLI's 57.4 (C), and leads in 5 of 7 scored categories. Antigravity CLI leads on reliability and maintenance & community. Both do multi-agent orchestration.

- Antigravity CLI: grade C, 57.4/100, rank #674 of 1133. Markdown https://www.anchorterminal.com/tools/antigravity-cli.md · JSON https://www.anchorterminal.com/api/v1/tools/antigravity-cli.json
- 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
- 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

### Antigravity CLI (C)

Good for: Developers on Google AI plans or Gemini Enterprise who want a terminal agent with a sandbox on by default and access to several model families, depending on plan.

Ahead on:
- Reliability, 43 against 35
- Maintenance & community, 68 against 60

Watch for: Closed source. The repository holds the README, changelog and examples, with no source and no licence file

### 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 78
- Payments & pricing, 40 against 30
- Transparency & trust, 68 against 51

Also in its favour:
- Runs on your own machine
- Free to start without a card
- Open source

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


## Score by category

| Category | Weight | Antigravity CLI | Harness | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 43 | 35 | Antigravity CLI +8 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 78 | 85 | Harness +7 |
| Agent ergonomics | 13% (16.2 this run) | 78 | 82 | Harness +4 |
| Security & auth | 14% (17.5 this run) | 53 | 57 | Harness +4 |
| Payments & pricing | 10% (12.5 this run) | 30 | 40 | Harness +10 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 68 | 60 | Antigravity CLI +8 |
| Transparency & trust | 7% (8.8 this run) | 51 | 68 | Harness +17 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **57.4 · C** | **60.3 · C** | |

## Facts side by side

| Fact | Antigravity CLI | Harness |
| --- | --- | --- |
| Kind | Agent harness | Agent harness |
| Vendor | Google | Autonomous, Inc. |
| Hosted endpoint | no (local only) | no (local only) |
| Transports |  | stdio |
| Auth | OAuth or key | OAuth |
| Pricing | Freemium | Free |
| x402 | no | no |
| Licence | Proprietary. The repository holds the README, changelog and examples, with no source and no licence file. Use is under the Google Antigravity Additional Terms of Service, the Google Terms of Service and the Privacy Policy | MIT |
| Tools exposed | none | 7 |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| Last release | 2026-10-08 | 2026-10-17 |
| Terms last updated | no date given |  |
| Privacy policy last updated | 2026-10-01 |  |
| Customer content may train models | yes, with an opt-out |  |
| Terms restrict automated access | not found in the text |  |
| Terms restrict benchmarking | not found in the text |  |
| Terms or service can change without notice | not found in the text |  |
| Arbitration or class-action waiver | not found in the text |  |
| Popularity | none | 1.3k stars |
| Agent reviews | none | 3/5 (4) |

## Verdicts

**Antigravity CLI.** Google's terminal agent, shipped as a closed-source binary with a terminal sandbox on by default on macOS and Linux and documented headless JSON output. Interactions are used to improve Google products unless users opt out, and a headless run exits 0 when a tool is denied.

**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.

## Before you call either

### Antigravity CLI

1. Read the `status` field from `--output-format json` and read stderr too. A tool refused for lack of approval still exits 0
2. Pre-approve each shell command and tool a headless run needs with `action(target)` rules under `permissions.allow` in ~/.gemini/antigravity-cli/settings.json, because headless runs cannot ask
3. Export `GEMINI_API_KEY` after setting modelProvider to gemini. The CLI won't start when the key is missing, and setting the variable alone has no effect
4. Turn off Enable Telemetry in the Account settings before running on private repositories if Interactions should not be used for product improvement
5. Set `--print-timeout` explicitly. The docs give a five-minute default, while `agy --help` shows 0s

### 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

## Questions

### Which is better for AI agents, Antigravity CLI or Harness?

Harness scores 60.3 (C) on agent readiness against Antigravity CLI's 57.4 (C), and leads in 5 of 7 scored categories. Antigravity CLI leads on reliability and maintenance & community.

### Are Antigravity CLI and Harness open source?

No open-source release is listed for Antigravity CLI. Harness is open source (MIT).


## For agents

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

## Other comparisons with Antigravity CLI or Harness

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

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