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Head to head · Agent harness · October 2026 research run

Devin vs Prime Agent

Prime Agent scores 60.5 (C) on agent readiness against Devin's 55.7 (C), and leads in 4 of 7 scored categories. Devin leads on schema & documentation, security & auth and transparency & trust. Both do agent harness.

DevinCognition AI, Inc. · Agent harness C55.7/100#447 of 629 Prime AgentPrime Intellect · Agent harness C60.5/100#352 of 629

Which one, for what

Devin C

Good 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 42
  • Security & auth, 72 against 50
  • Transparency & trust, 69 against 64

Also in its favour

  • A hosted endpoint, with nothing to install

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

Prime Agent C

Good for Long-running research and coding work where one model drives subagents, schedules and goals from code, and where the owner can isolate the machine.

Ahead on

  • Reliability, 65 against 30
  • Agent ergonomics, 73 against 62
  • Payments & pricing, 60 against 20
  • Maintenance & community, 79 against 63

Also in its favour

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

Watch for

No approval prompts and no sandbox. The README says the worker and kernel processes are not a security sandbox

Score by category

CategoryWeight this runDevinPrime AgentEdge
Reliability16%203065Prime Agent +35
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.28042Devin +38
Agent ergonomics13%16.26273Prime Agent +11
Security & auth14%17.57250Devin +22
Payments & pricing10%12.52060Prime Agent +40
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.86379Prime Agent +16
Transparency & trust7%8.86964Devin +5
Negative events≤1500
Total55.7 · C60.5 · C

Facts side by side

FactDevinPrime Agent
KindAgent harnessAgent harness
VendorCognition AI, Inc.Prime Intellect
Hosted endpointhttps://mcp.devin.ai/mcpno (local only)
TransportsHTTP
AuthAPI keyNone
PricingFreemiumFree
x402nono
LicenceProprietary service under Cognition's Platform Terms of ServiceMIT
Tools exposed13none
Read-only variant documentedyesno
llms.txtyesno
Last release2026-10-072026-10-07
Terms last updated2026-06-30no date given
Privacy policy last updated2026-03-09no date given
Customer content may train modelsyes, with an opt-outnot found in the text
Terms restrict automated accessnot found in the textyes
Terms restrict benchmarkingyesyes
Terms or service can change without noticenot found in the textyes
Arbitration or class-action waiveryesyes
Popularitynone22k stars

Verdicts

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.

Prime Agent

Budgets for turns, tokens and time bound an autonomous run, and sessions survive a closed terminal through a supervising daemon. Model-written Python and shell commands run with the user's rights, with no approval step and no sandbox, and the Rust build on the main branch ships only as nightly betas.

Before you call either

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

Prime Agent

  1. Run it in a disposable clone, container or VM. It executes model-written Python and shell commands with the user's rights and asks nothing first
  2. Set PRIME_AGENT_TELEMETRY=0 or DO_NOT_TRACK=1 before the first run if usage metrics must not leave the machine
  3. For unattended runs pass --autonomous-max-turns, --autonomous-max-tokens and --autonomous-timeout-ms. Reaching a limit does not mean the task succeeded
  4. Headless use is -p with --mode json per the argument parser. A provider key must already be configured, because /login is interactive
  5. The -t/--tools, -nt/--no-tools and -nbt/--no-builtin-tools flags were removed and now fail as unknown options

Questions

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

Prime Agent scores 60.5 (C) on agent readiness against Devin's 55.7 (C), and leads in 4 of 7 scored categories. Devin leads on schema & documentation, security & auth and transparency & trust.

Are Devin and Prime Agent open source?

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

Other comparisons with Devin or Prime Agent

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