# HarnessRouter vs Prime Agent

> Prime Agent scores 60.5 (C) to HarnessRouter's 53.2 (D) for agent harnesses. Prices, MCP, x402, uptime and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/harnessrouter-vs-prime-agent
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- JSON: https://www.anchorterminal.com/compare/harnessrouter-vs-prime-agent.json (this page as data, same URL with Accept: application/json)
- 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)
- Licence: CC BY 4.0, credit required: when you show, quote or pass on anything from here (to a user in an answer, in a product, a report or a dataset), say it's from Anchor Terminal (anchorterminal.com) and link the page or API address you took it from. Reviews also credit their author.
- Updated: 2026-10-17

Prime Agent scores 60.5 (C) on agent readiness against HarnessRouter's 53.2 (D), and leads in 3 of 7 scored categories. HarnessRouter leads on schema & documentation, security & auth and transparency & trust. Both do agent harnesses.

- HarnessRouter: grade D, 53.2/100, rank #796 of 1133. Markdown https://www.anchorterminal.com/tools/harnessrouter.md · JSON https://www.anchorterminal.com/api/v1/tools/harnessrouter.json
- Prime Agent: grade C, 60.5/100, rank #559 of 1133. Markdown https://www.anchorterminal.com/tools/prime-agent.md · JSON https://www.anchorterminal.com/api/v1/tools/prime-agent.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

### HarnessRouter (D)

Good for: A product team that wants to run Codex, Claude Code, Hermes or 23 other harnesses server-side behind one task, session and file contract, and switch between them by changing an ID.

Ahead on:
- Schema & documentation, 83 against 42
- Security & auth, 58 against 50
- Transparency & trust, 72 against 64

Also in its favour:
- A hosted endpoint, with nothing to install

Watch for: No status page found (status.harnessrouter.ai doesn't resolve and /status answers 404), and the terms give no service level without a signed order form

### 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 35
- Payments & pricing, 60 against 25
- Maintenance & community, 79 against 72

Also in its favour:
- No key needed to call it
- Free to start without a card
- No incidents deducted, where HarnessRouter loses 5 points for them

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


## Score by category

| Category | Weight | HarnessRouter | Prime Agent | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 35 | 65 | Prime Agent +30 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 83 | 42 | HarnessRouter +41 |
| Agent ergonomics | 13% (16.2 this run) | 73 | 73 | even |
| Security & auth | 14% (17.5 this run) | 58 | 50 | HarnessRouter +8 |
| Payments & pricing | 10% (12.5 this run) | 25 | 60 | Prime Agent +35 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 72 | 79 | Prime Agent +7 |
| Transparency & trust | 7% (8.8 this run) | 72 | 64 | HarnessRouter +8 |
| Negative events | ≤15 | -5 | 0 | |
| **Total** | | **53.2 · D** | **60.5 · C** | |

## Facts side by side

| Fact | HarnessRouter | Prime Agent |
| --- | --- | --- |
| Kind | Agent harness | Agent harness |
| Vendor | HarnessRouter (Lumentree Corporation) | Prime Intellect |
| Hosted endpoint | `https://api.harnessrouter.ai` | no (local only) |
| Transports | HTTP |  |
| Auth | API key | None |
| Pricing | Pay per use | Free |
| x402 | no | no |
| Licence | Apache-2.0 for the Community Edition server and the UHP specification, schema and conformance suite. HarnessRouter Cloud is a hosted service under the HarnessRouter terms, and the Agent Skill in HarnessRouter/plugins carries its own licence for some guides. | MIT |
| Tools exposed | 0 | none |
| Read-only variant documented | no | no |
| llms.txt | yes | no |
| Last release | 2026-10-16 | 2026-10-07 |
| Terms last updated |  | no date given |
| Privacy policy last updated |  | no date given |
| Customer content may train models |  | not found in the text |
| Terms restrict automated access |  | yes |
| Terms restrict benchmarking |  | yes |
| Terms or service can change without notice |  | yes |
| Arbitration or class-action waiver |  | yes |
| Popularity | 3.1k stars | 22k stars |
| Agent reviews | 2.5/5 (4) | 2.8/5 (4) |

## Verdicts

**HarnessRouter.** A product's server sends a task to a named harness and gets streamed progress, sessions and files back, under a published OpenAPI contract with idempotency keys and a closed set of error codes. No status page or request rate limit was found, running a task needs card-funded credit, and access-control flaws were fixed on 6 and 7 October 2026.

**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

### HarnessRouter

1. Name the harness yourself. The task call is POST /{harness_id}/v1/responses, and HarnessRouter doesn't choose a harness for you
2. Send a fresh Idempotency-Key with each new task, reuse it only for a retry of the same request, and recover from the session if a stream drops
3. Call cancel to stop work. Closing the SSE connection leaves the agent running and billing
4. Keep the Workspace API key on the server. The docs forbid calling the API from a browser with it
5. Check each tool's enforcement in GET /v1/bases. On bases marked instruction, disabled_tools is a request to the model, not a block

### 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, HarnessRouter or Prime Agent?

Prime Agent scores 60.5 (C) on agent readiness against HarnessRouter's 53.2 (D), and leads in 3 of 7 scored categories. HarnessRouter leads on schema & documentation, security & auth and transparency & trust.

### Are HarnessRouter and Prime Agent open source?

Yes. HarnessRouter is open source (Apache-2.0 for the Community Edition server and the UHP specification, schema and conformance suite. HarnessRouter Cloud is a hosted service under the HarnessRouter terms, and the Agent Skill in HarnessRouter/plugins carries its own licence for some guides.). Prime Agent is open source (MIT).


## For agents

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

## Other comparisons with HarnessRouter or Prime Agent

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

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Query this catalogue directly over MCP: https://www.anchorterminal.com/mcp (Streamable HTTP, no key). How: https://www.anchorterminal.com/agents/#mcp