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Head to head · Agent harnesses · October 2026 research run

Agent Zero vs Devin

Devin scores 55.7 (C) on agent readiness against Agent Zero's 54.2 (C), and leads in 3 of 7 scored categories. Agent Zero leads on reliability, payments & pricing and maintenance & community. 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 DevinCognition AI, Inc. · Agent harness C55.7/100#667 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

  • Reliability, 57 against 30
  • Payments & pricing, 60 against 20
  • Maintenance & community, 75 against 63

Also in its favour

  • No key needed to call it
  • Open source

Watch for

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

Devin C

Best for A team that wants to hand whole tasks to a cloud agent and collect pull requests, driven from a pipeline or another agent.

Ahead on

  • Schema & documentation, 80 against 64
  • Security & auth, 72 against 54
  • Transparency & trust, 69 against 55

Also in its favour

  • A hosted endpoint, with nothing to install
  • No incidents deducted, where Agent Zero loses 6 points for them

Watch for

www.devinstatus.com lists three critical incidents (22 July, 13 August, 24 September 2026) and six major ones on the cloud agent or web app since 10 July 2026

Score by category

CategoryWeight this runAgent ZeroDevinEdge
Reliability16%205730Agent Zero +27
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.26480Devin +16
Agent ergonomics13%16.26262even
Security & auth14%17.55472Devin +18
Payments & pricing10%12.56020Agent Zero +40
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.87563Agent Zero +12
Transparency & trust7%8.85569Devin +14
Negative events≤15-60
TotalC 54.2/100C 55.7/100

Facts side by side

FactAgent ZeroDevin
KindAgent harnessAgent harness
VendorAgent Zero, s.r.o.Cognition AI, Inc.
Hosted endpointno (local only)https://mcp.devin.ai/mcp
TransportsHTTP
AuthNoneAPI key
PricingFreeFreemium
x402nono
LicenceMITProprietary service under Cognition's Platform Terms of Service
Tools exposednone13
Read-only variant documentednoyes
llms.txtyesyes
Last release2026-09-232026-10-07
Terms last updatedno document linked2026-06-30
Privacy policy last updatedno document linked2026-03-09
Customer content may train modelsyes, with an opt-out
Terms restrict automated accessnot found in the text
Terms restrict benchmarkingyes
Terms or service can change without noticenot found in the text
Arbitration or class-action waiveryes
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.

Devin

The v3 API is well specified, with a public OpenAPI 3.1 file covering 239 operations, problem+json errors, cursor pagination and service-user keys tied to roles. The status page records three critical and several major incidents on the cloud agent between 22 July and 24 September 2026, and no rate limit figures or retry guidance were found in the reviewed documentation.

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

Devin

  1. Use a cog_ service-user key with the Member role. Legacy apk_ keys fail against v3 and the MCP server with 401 or 403
  2. Set max_acu_limit on every session you create. Usage is metered by the work done and has no published unit rate
  3. Session creation is not idempotent in v3. After a timeout, list sessions by tag before creating again
  4. Enterprise keys and personal access tokens must send X-Org-Id to the MCP server. Organisation-scoped keys resolve it automatically
  5. Create scheduled work as an automation. POST to the schedules endpoint returns 403 for migrated organisations since 24 September 2026

Questions

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

Devin scores 55.7 (C) on agent readiness against Agent Zero's 54.2 (C), and leads in 3 of 7 scored categories. Agent Zero leads on reliability, payments & pricing and maintenance & community.

Are Agent Zero and Devin open source?

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

Other comparisons with Agent Zero or Devin

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