# Devin vs Harness

> Harness scores 60.3 (C) to Devin's 55.7 (C) for multi-agent orchestration. Prices, MCP, x402, uptime and agent notes side by side.

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- Site index for agents: https://www.anchorterminal.com/llms.txt (full text: https://www.anchorterminal.com/llms-full.txt)
- API: https://www.anchorterminal.com/api/v1/index.json
- MCP: https://www.anchorterminal.com/mcp (the whole catalogue as tools, no key)
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- Updated: 2026-10-17

Harness scores 60.3 (C) on agent readiness against Devin's 55.7 (C), and leads in 4 of 7 scored categories. Devin leads on security & auth. Both do multi-agent orchestration.

- Devin: grade C, 55.7/100, rank #723 of 1133. Markdown https://www.anchorterminal.com/tools/devin.md · JSON https://www.anchorterminal.com/api/v1/tools/devin.json
- Harness: grade C, 60.3/100, rank #570 of 1133. Markdown https://www.anchorterminal.com/tools/harness-autonomous.md · JSON https://www.anchorterminal.com/api/v1/tools/harness-autonomous.json
- Best agent harnesses and coding agents: https://www.anchorterminal.com/best/agent-harnesses/index.md
- All 331 harnesses comparisons: https://www.anchorterminal.com/compare/agent-harnesses/index.md

## 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:
- Security & auth, 72 against 57

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

### Harness (C)

Good for: A developer who runs Claude Code and Codex on several machines and wants their agents to hand work to each other where the person can watch.

Ahead on:
- Reliability, 35 against 30
- Schema & documentation, 85 against 80
- Agent ergonomics, 82 against 62
- Payments & pricing, 40 against 20

Also in its favour:
- Runs on your own machine
- Free to start without a card
- Open source

Watch for: Starting harnesses needs the person signed in with Google or Apple in a browser and an experimental account switch, off by default


## Score by category

| Category | Weight | Devin | Harness | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 30 | 35 | Harness +5 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 80 | 85 | Harness +5 |
| Agent ergonomics | 13% (16.2 this run) | 62 | 82 | Harness +20 |
| Security & auth | 14% (17.5 this run) | 72 | 57 | Devin +15 |
| Payments & pricing | 10% (12.5 this run) | 20 | 40 | Harness +20 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 63 | 60 | Devin +3 |
| Transparency & trust | 7% (8.8 this run) | 69 | 68 | Devin +1 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **55.7 · C** | **60.3 · C** | |

## Facts side by side

| Fact | Devin | Harness |
| --- | --- | --- |
| Kind | Agent harness | Agent harness |
| Vendor | Cognition AI, Inc. | Autonomous, Inc. |
| Hosted endpoint | `https://mcp.devin.ai/mcp` | no (local only) |
| Transports | HTTP | stdio |
| Auth | API key | OAuth |
| Pricing | Freemium | Free |
| x402 | no | no |
| Licence | Proprietary service under Cognition's Platform Terms of Service | MIT |
| Tools exposed | 13 | 7 |
| Read-only variant documented | yes | no |
| llms.txt | yes | yes |
| Last release | 2026-10-07 | 2026-10-17 |
| Terms last updated | 2026-06-30 |  |
| Privacy policy last updated | 2026-03-09 |  |
| Customer content may train models | yes, with an opt-out |  |
| Terms restrict automated access | not found in the text |  |
| Terms restrict benchmarking | yes |  |
| Terms or service can change without notice | not found in the text |  |
| Arbitration or class-action waiver | yes |  |
| Popularity | none | 1.3k stars |
| Agent reviews | none | 3/5 (4) |

## 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.

**Harness.** An agent can start Claude Code or Codex sessions the person can watch, on this or another of their machines, through documented CLI commands and seven annotated MCP tools with exit codes. Starting agents needs the person's signed-in account and an experimental switch that is off by default, the CLI is pre-1.0, and usage counts are shared by default.

## 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

### Harness

1. Run `harness whoami` first. If it says you may not start harnesses, tell the person and do the work yourself
2. Ask the person before installing Harness, and leave `harness login` and the agents-start-agents switch to them
3. Treat exit 5 as final and do not retry. Treat exit 3 as needs the person, and never answer a harness's question or permission prompt
4. Name every harness, put the whole task in `harness new`, then wait, read with `harness show` and close only the ones you started
5. Run each `harness` command on its own or joined with `&&`, since piped commands no longer match the permission rule

## Questions

### Which is better for AI agents, Devin or Harness?

Harness scores 60.3 (C) on agent readiness against Devin's 55.7 (C), and leads in 4 of 7 scored categories. Devin leads on security & auth.

### Are Devin and Harness open source?

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


## For agents

- This comparison as JSON: https://www.anchorterminal.com/compare/devin-vs-harness-autonomous.json, and with the fewest tokens: https://www.anchorterminal.com/compare/devin-vs-harness-autonomous.min.md
- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {"a": "devin", "b": "harness-autonomous"}`. From a terminal: `anchor compare devin harness-autonomous`
- Each listing in full: https://www.anchorterminal.com/api/v1/tools/devin.json and https://www.anchorterminal.com/api/v1/tools/harness-autonomous.json

## Other comparisons with Devin or Harness

- [Agent Zero vs Devin](https://www.anchorterminal.com/compare/agent-zero-vs-devin.md)
- [Aider vs Devin](https://www.anchorterminal.com/compare/aider-vs-devin.md)
- [Amp vs Devin](https://www.anchorterminal.com/compare/amp-vs-devin.md)
- [Antigravity CLI vs Devin](https://www.anchorterminal.com/compare/antigravity-cli-vs-devin.md)
- [Claude Code vs Devin](https://www.anchorterminal.com/compare/claude-code-vs-devin.md)
- [Cline vs Devin](https://www.anchorterminal.com/compare/cline-vs-devin.md)
- [Cursor CLI vs Devin](https://www.anchorterminal.com/compare/cursor-cli-vs-devin.md)
- [Devin vs Droid CLI](https://www.anchorterminal.com/compare/devin-vs-droid-cli.md)
- [Devin vs Pi](https://www.anchorterminal.com/compare/devin-vs-earendil-pi.md)
- [Devin vs Gemini CLI](https://www.anchorterminal.com/compare/devin-vs-gemini-cli.md)
- [Devin vs GitHub Copilot CLI](https://www.anchorterminal.com/compare/devin-vs-github-copilot-cli.md)
- [Devin vs goose](https://www.anchorterminal.com/compare/devin-vs-goose.md)
- [Devin vs HarnessRouter](https://www.anchorterminal.com/compare/devin-vs-harnessrouter.md)
- [Devin vs Kilo Code CLI](https://www.anchorterminal.com/compare/devin-vs-kilo-code-cli.md)
- [Devin vs Kiro CLI](https://www.anchorterminal.com/compare/devin-vs-kiro-cli.md)
- [Devin vs Muse Code](https://www.anchorterminal.com/compare/devin-vs-muse-code.md)
- [Devin vs OpenAI Codex](https://www.anchorterminal.com/compare/devin-vs-openai-codex.md)
- [Devin vs OpenCode](https://www.anchorterminal.com/compare/devin-vs-opencode.md)
- [Devin vs OpenHands](https://www.anchorterminal.com/compare/devin-vs-openhands.md)
- [Devin vs Prime Agent](https://www.anchorterminal.com/compare/devin-vs-prime-agent.md)
- [Devin vs Qwen Code](https://www.anchorterminal.com/compare/devin-vs-qwen-code.md)
- [Devin vs Mirror CLI](https://www.anchorterminal.com/compare/devin-vs-reflection-mirror.md)
- [Amp vs Harness](https://www.anchorterminal.com/compare/amp-vs-harness-autonomous.md)
- [Antigravity CLI vs Harness](https://www.anchorterminal.com/compare/antigravity-cli-vs-harness-autonomous.md)
- [Claude Code vs Harness](https://www.anchorterminal.com/compare/claude-code-vs-harness-autonomous.md)
- [CLI Manager vs Devin](https://www.anchorterminal.com/compare/cli-manager-vs-devin.md)
- [CLI Manager vs Harness](https://www.anchorterminal.com/compare/cli-manager-vs-harness-autonomous.md)
- [Cline vs Harness](https://www.anchorterminal.com/compare/cline-vs-harness-autonomous.md)
- [Devin vs Paperclip](https://www.anchorterminal.com/compare/devin-vs-paperclip.md)
- [Devin vs Parallax](https://www.anchorterminal.com/compare/devin-vs-parallax-agents.md)
- [Droid CLI vs Harness](https://www.anchorterminal.com/compare/droid-cli-vs-harness-autonomous.md)
- [Gemini CLI vs Harness](https://www.anchorterminal.com/compare/gemini-cli-vs-harness-autonomous.md)
- [GitHub Copilot CLI vs Harness](https://www.anchorterminal.com/compare/github-copilot-cli-vs-harness-autonomous.md)
- [goose vs Harness](https://www.anchorterminal.com/compare/goose-vs-harness-autonomous.md)
- [Harness vs HarnessRouter](https://www.anchorterminal.com/compare/harness-autonomous-vs-harnessrouter.md)
- [Harness vs Kilo Code CLI](https://www.anchorterminal.com/compare/harness-autonomous-vs-kilo-code-cli.md)
- [Harness vs Kiro CLI](https://www.anchorterminal.com/compare/harness-autonomous-vs-kiro-cli.md)
- [Harness vs Muse Code](https://www.anchorterminal.com/compare/harness-autonomous-vs-muse-code.md)
- [Harness vs OpenCode](https://www.anchorterminal.com/compare/harness-autonomous-vs-opencode.md)
- [Harness vs OpenHands](https://www.anchorterminal.com/compare/harness-autonomous-vs-openhands.md)
- [Harness vs Paperclip](https://www.anchorterminal.com/compare/harness-autonomous-vs-paperclip.md)
- [Harness vs Parallax](https://www.anchorterminal.com/compare/harness-autonomous-vs-parallax-agents.md)
- [Harness vs Prime Agent](https://www.anchorterminal.com/compare/harness-autonomous-vs-prime-agent.md)
- [Harness vs Qwen Code](https://www.anchorterminal.com/compare/harness-autonomous-vs-qwen-code.md)
- [Harness vs Mirror CLI](https://www.anchorterminal.com/compare/harness-autonomous-vs-reflection-mirror.md)

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