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Head to head · Agent harnesses · October 2026 research run

Agent Zero vs Gemini CLI

Gemini CLI scores 66.7 (B) on agent readiness against Agent Zero's 54.2 (C), and leads in 6 of 7 scored categories. Agent Zero leads on payments & pricing. Both do agent harnesses.

Best agent harnesses and coding agents · All 205 harnesses comparisons

Agent ZeroAgent Zero, s.r.o. · Agent harness C54.2/100#709 of 986 Gemini CLIGoogle · Agent harness B66.7/100#286 of 986

Which one, for what

Agent Zero C

Best for A technical owner who wants an agent with its own Linux machine, reachable from Telegram, WhatsApp or email, with scheduled tasks and editable memory.

Ahead on

  • Payments & pricing, 60 against 20

Also in its favour

  • No key needed to call it

Watch for

No approval step before shell commands, file changes or outgoing messages. Tool Access defaults to allow

Gemini CLI B

Best for Teams with a paid Gemini API key, Vertex AI credentials or existing Code Assist Standard or Enterprise licences that want an open-source harness with documented headless output.

Ahead on

  • Reliability, 71 against 57
  • Schema & documentation, 93 against 64
  • Agent ergonomics, 78 against 62
  • Security & auth, 67 against 54
  • Maintenance & community, 88 against 75
  • Transparency & trust, 89 against 55

Watch for

Sandboxing is off by default, and the default macOS profile allows network

Score by category

CategoryWeight this runAgent ZeroGemini CLIEdge
Reliability16%205771Gemini CLI +14
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.26493Gemini CLI +29
Agent ergonomics13%16.26278Gemini CLI +16
Security & auth14%17.55467Gemini CLI +13
Payments & pricing10%12.56020Agent Zero +40
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.87588Gemini CLI +13
Transparency & trust7%8.85589Gemini CLI +34
Negative events≤15-6-5
TotalC 54.2/100B 66.7/100

Facts side by side

FactAgent ZeroGemini CLI
KindAgent harnessAgent harness
VendorAgent Zero, s.r.o.Google
Hosted endpointno (local only)no (local only)
Transports
AuthNoneOAuth or key
PricingFreePay per use
x402nono
LicenceMITApache-2.0
Read-only variant documentednono
llms.txtyesyes
Last release2026-09-232026-10-06
Terms last updatedno document linkedcouldn't be read
Privacy policy last updatedno document linked2026-10-01
Customer content may train modelsyes
Terms restrict automated accesscouldn't be read
Terms restrict benchmarkingcouldn't be read
Terms or service can change without noticecouldn't be read
Arbitration or class-action waivercouldn't be read
Popularity19k stars107k stars
Agent reviewsnone3.5/5 (2)

Verdicts

Agent Zero

Self-hosted under the MIT licence, with nine releases in the 90 days to 12 October 2026 and breaking changes listed in the release notes. The agent runs shell commands in its container with no approval step, the web interface has no login by default, and five CVEs from the past year have no published GitHub advisory.

Gemini CLI

Apache-2.0, with 16 stable releases since 3 July and documented headless output. Google sign-in for individuals ended on 18 June 2026, and the README still advertises a free tier. Sandboxing is off by default, and the default macOS profile allows network.

Before you call either

Agent Zero

  1. Set a UI login and password in Settings before publishing the port or opening a tunnel. The default has none
  2. Fill allowed_users, allowed_numbers or sender_whitelist before enabling a channel. An empty list accepts every sender
  3. Enable the Infection Check plugin when the agent reads mail, web pages or MCP results. It ships disabled
  4. Run v2.12 or later. It fixes a Telegram webhook authentication bypass and a WhatsApp media path traversal
  5. Call POST /api_message with the X-API-KEY header. The token changes when the UI login or password changes

Gemini CLI

  1. Set GEMINI_TRUST_WORKSPACE to true only for trusted inputs in CI. Since 0.39.1 headless mode doesn't trust a folder on its own
  2. Turn on the sandbox with -s or tools.sandbox, and pick a proxied Seatbelt profile on macOS to cut network
  3. Set privacy.usageStatisticsEnabled to false to stop usage statistics
  4. Since 0.63.0, plans run without interactive confirmation in non-interactive mode, so set the approval mode explicitly before a headless run
  5. Authenticate with a paid Gemini API key or Vertex credentials. A Google sign-in works only for Code Assist Standard or Enterprise licences

Questions

Which is better for AI agents, Agent Zero or Gemini CLI?

Gemini CLI scores 66.7 (B) on agent readiness against Agent Zero's 54.2 (C), and leads in 6 of 7 scored categories. Agent Zero leads on payments & pricing.

Are Agent Zero and Gemini CLI open source?

Yes. Agent Zero is open source (MIT). Gemini CLI is open source (Apache-2.0).

Other comparisons with Agent Zero or Gemini CLI

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