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Head to head · Agent harnesses · October 2026 research run

Agent Zero vs Unstoppable

Agent Zero scores 54.3 (C) on agent readiness against Unstoppable's 34.9 (F), and leads in 6 of 7 scored categories. Both do agent harnesses.

Best agent harnesses and coding agents · All 833 harnesses comparisons

Agent ZeroAgent Zero, s.r.o. · Agent harness C54.3/100#804 of 1217 UnstoppableUnstoppable Domains, Inc. · Agent harness F34.9/100#1132 of 1217

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

  • Reliability, 57 against 45
  • Schema & documentation, 64 against 30
  • Agent ergonomics, 62 against 5
  • Security & auth, 54 against 36
  • Payments & pricing, 60 against 30
  • Maintenance & community, 75 against 58

Also in its favour

  • Open source

Watch for

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

Unstoppable F

Best for A developer who runs Claude Code, Codex and Cursor on existing plans and wants parallel worktrees, pipelines and phone check-ins in one app.

Also in its favour

  • Free to start without a card
  • No incidents deducted, where Agent Zero loses 6 points for them

Watch for

No API, MCP server, SDK or documented CLI for an outside agent. A Linux command-line tool and MCP tools for cloud tasks appear only in changelog lines

Score by category

CategoryWeight this runAgent ZeroUnstoppableEdge
Reliability16%205745Agent Zero +12
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.26430Agent Zero +34
Agent ergonomics13%16.2625Agent Zero +57
Security & auth14%17.55436Agent Zero +18
Payments & pricing10%12.56030Agent Zero +30
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.87558Agent Zero +17
Transparency & trust7%8.85658Unstoppable +2
Negative events≤15-60
TotalC 54.3/100F 34.9/100

Facts side by side

FactAgent ZeroUnstoppable
KindAgent harnessAgent harness
VendorAgent Zero, s.r.o.Unstoppable Domains, Inc.
Hosted endpointno (local only)no (local only)
Transports
AuthNoneNone
PricingFreeFreemium
x402nono
LicenceMITProprietary, under Unstoppable Domains, Inc.'s Terms of Service. No source published
Read-only variant documentednono
llms.txtyesyes
Last release2026-09-232026-10-23
Terms last updatedno document linked
Privacy policy last updatedno document linked
Customer content may train models
Terms restrict automated access
Terms restrict benchmarking
Terms or service can change without notice
Arbitration or class-action waiver
Popularity19k starsnone

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.

Unstoppable

Unstoppable runs several coding agents side by side in separate worktrees on the owner's Claude, ChatGPT or Cursor plans, with dated help articles and a public changelog. It has no API, MCP server or documented command an outside agent can call, every chat starts in Full access, and its pages disagree on which parts need a paid plan.

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

Unstoppable

  1. Don't plan to drive Unstoppable from another agent. It has no documented API, MCP server or CLI. Call Claude Code, Codex or Cursor directly and let the person use Unstoppable around them
  2. Inside Unstoppable, check the approval mode before acting. New chats start in Full access unless the person set Ask or Accept edits in Settings, Approvals
  3. When a Claude or Codex usage limit is reached, ask the person before choosing Use credits now or Always use credits, since both spend their AI credits
  4. Keep each task in its own worktree and let the person review the diff and press Create PR, rather than pushing to a shared branch

Questions

Which is better for AI agents, Agent Zero or Unstoppable?

Agent Zero scores 54.3 (C) on agent readiness against Unstoppable's 34.9 (F), and leads in 6 of 7 scored categories.

Are Agent Zero and Unstoppable open source?

Agent Zero is open source (MIT). No open-source release is listed for Unstoppable.

Other comparisons with Agent Zero or Unstoppable

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