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Head to head · Multi-agent orchestration · October 2026 research run

Antigravity CLI vs 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. Both do multi-agent orchestration.

Best agent harnesses and coding agents · All 331 harnesses comparisons

Antigravity CLIGoogle · Agent harness C57.4/100#674 of 1133 HarnessAutonomous, Inc. · Agent harness C60.3/100#570 of 1133

Which one, for what

Antigravity CLI C

Best 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

Best 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

CategoryWeight this runAntigravity CLIHarnessEdge
Reliability16%204335Antigravity CLI +8
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.27885Harness +7
Agent ergonomics13%16.27882Harness +4
Security & auth14%17.55357Harness +4
Payments & pricing10%12.53040Harness +10
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.86860Antigravity CLI +8
Transparency & trust7%8.85168Harness +17
Negative events≤1500
TotalC 57.4/100C 60.3/100

Facts side by side

FactAntigravity CLIHarness
KindAgent harnessAgent harness
VendorGoogleAutonomous, Inc.
Hosted endpointno (local only)no (local only)
Transportsstdio
AuthOAuth or keyOAuth
PricingFreemiumFree
x402nono
LicenceProprietary. 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 PolicyMIT
Tools exposednone7
Read-only variant documentednono
llms.txtyesyes
Last release2026-10-082026-10-17
Terms last updatedno date given
Privacy policy last updated2026-10-01
Customer content may train modelsyes, with an opt-out
Terms restrict automated accessnot found in the text
Terms restrict benchmarkingnot found in the text
Terms or service can change without noticenot found in the text
Arbitration or class-action waivernot found in the text
Popularitynone1.3k stars
Agent reviewsnone3/5 (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).

Other comparisons with Antigravity CLI or Harness

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