Head to head · Agent harnesses · October 2026 research run

Jules vs Unstoppable

Jules scores 44.7 (E) on agent readiness against Unstoppable's 34.9 (F), and leads in 3 of 7 scored categories. Unstoppable leads on reliability, maintenance & community and transparency & trust. Both do agent harnesses.

Best agent harnesses and coding agents · All 833 harnesses comparisons

Which one, for what

Jules E

Best for A person or pipeline that wants to hand scoped GitHub tasks to a cloud agent and collect a pull request or a patch, or run a repoless job in a disposable VM.

Ahead on

  • Schema & documentation, 76 against 30
  • Agent ergonomics, 64 against 5
  • Security & auth, 57 against 36

Also in its favour

  • Runs on your own machine

Watch for

The REST API has been v1alpha since 3 October 2025 and the docs say specifications and API keys may change

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.

Ahead on

  • Reliability, 45 against 13
  • Maintenance & community, 58 against 18
  • Transparency & trust, 58 against 46

Also in its favour

  • No key needed to call it
  • Free to start without a card

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 runJulesUnstoppableEdge
Reliability16%201345Unstoppable +32
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.27630Jules +46
Agent ergonomics13%16.2645Jules +59
Security & auth14%17.55736Jules +21
Payments & pricing10%12.53030even
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.81858Unstoppable +40
Transparency & trust7%8.84658Unstoppable +12
Negative events≤1500
TotalE 44.7/100F 34.9/100

Facts side by side

FactJulesUnstoppable
KindAgent harnessAgent harness
VendorGoogle LLCUnstoppable Domains, Inc.
Hosted endpointno (local only)no (local only)
TransportsHTTP, stdio
AuthOAuth or keyNone
PricingFreemiumFreemium
x402nono
LicenceProprietary service under the Google Terms of Service. The TypeScript SDK is Apache-2.0; the CLI binary is closedProprietary, under Unstoppable Domains, Inc.'s Terms of Service. No source published
Tools exposed8none
Read-only variant documentednono
llms.txtyesyes
Last release2026-03-092026-10-23
Terms last updated2026-07-30
Privacy policy last updated2026-10-01
Customer content may train modelsyes
Terms restrict automated accessyes
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
Popularity1.3k npm/wknone
Agent reviews2.8/5 (4)none

Verdicts

Jules

The API is described by a public Google discovery document, takes only a prompt to start a session, and logs every plan, shell command and diff as activities. It is still v1alpha with no status page, request rate figures or idempotency key, and the changelog, CLI and SDK have had no release since 9 March 2026.

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

Jules

  1. Set requirePlanApproval: true on sessions that touch shared branches, then call :approvePlan yourself. API sessions otherwise run their plan without review
  2. Session creation has no request ID. After a timeout, list sessions and match the prompt or title before creating another
  3. Poll activities with a create_time filter and cache them. Activities never change once written
  4. Read the request fields from the discovery document at https://jules.googleapis.com/$discovery/rest?version=v1alpha. The field tables on jules.google render empty
  5. Budget against the daily task quota of 15, 100 or 300 by plan. New sessions are refused until the rolling 24 hours reset

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, Jules or Unstoppable?

Jules scores 44.7 (E) on agent readiness against Unstoppable's 34.9 (F), and leads in 3 of 7 scored categories. Unstoppable leads on reliability, maintenance & community and transparency & trust.

Other comparisons with Jules or Unstoppable

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