Head to head · Agent harnesses · October 2026 research run

Antigravity CLI vs Mirror CLI

Antigravity CLI scores 57.4 (C) on agent readiness against Mirror CLI's 54.2 (C), and leads in 4 of 7 scored categories. Mirror CLI leads on security & auth, payments & pricing and transparency & trust. Both do agent harnesses.

Best agent harnesses and coding agents · All 331 harnesses comparisons

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 37
  • Schema & documentation, 78 against 65
  • Agent ergonomics, 78 against 58
  • Maintenance & community, 68 against 47

Watch for

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

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

  • Security & auth, 58 against 53
  • Payments & pricing, 60 against 30
  • Transparency & trust, 58 against 51

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 runAntigravity CLIMirror CLIEdge
Reliability16%204337Antigravity CLI +6
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.27865Antigravity CLI +13
Agent ergonomics13%16.27858Antigravity CLI +20
Security & auth14%17.55358Mirror CLI +5
Payments & pricing10%12.53060Mirror CLI +30
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.86847Antigravity CLI +21
Transparency & trust7%8.85158Mirror CLI +7
Negative events≤1500
TotalC 57.4/100C 54.2/100

Facts side by side

FactAntigravity CLIMirror CLI
KindAgent harnessAgent harness
VendorGoogleReflection
Hosted endpointno (local only)no (local only)
Transports
AuthOAuth or keyAPI key
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 PolicyApache-2.0
Read-only variant documentednono
llms.txtyesyes
Last release2026-10-082026-10-16
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
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.

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

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

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, Antigravity CLI or Mirror CLI?

Antigravity CLI scores 57.4 (C) on agent readiness against Mirror CLI's 54.2 (C), and leads in 4 of 7 scored categories. Mirror CLI leads on security & auth, payments & pricing and transparency & trust.

Are Antigravity CLI and Mirror CLI open source?

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

Other comparisons with Antigravity CLI or Mirror CLI

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