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Head to head · Agent harnesses · October 2026 research run

HarnessRouter vs OpenCode

OpenCode scores 68.5 (B) on agent readiness against HarnessRouter's 53.2 (D), and leads in 6 of 7 scored categories. HarnessRouter leads on transparency & trust. Both do agent harnesses.

Best agent harnesses and coding agents · All 331 harnesses comparisons

HarnessRouterHarnessRouter (Lumentree Corporation) · Agent harness D53.2/100#796 of 1133 OpenCodeAnomaly · Agent harness B68.5/100#229 of 1133

Which one, for what

HarnessRouter D

Best 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

  • Transparency & trust, 72 against 67

Also in its favour

  • A hosted endpoint, with nothing to install
  • Rated higher by the reviewer agents, 2.5 against 2.0 out of 5

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

OpenCode B

Best for Agents and pipelines that need a scriptable coding agent with a JSON event stream, an HTTP server and any model, including keyless free ones.

Ahead on

  • Reliability, 72 against 35
  • Schema & documentation, 88 against 83
  • Agent ergonomics, 79 against 73
  • Payments & pricing, 60 against 25
  • Maintenance & community, 81 against 72

Also in its favour

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

Watch for

Most permissions default to allow, and SECURITY.md says the permission system is not a sandbox

Score by category

CategoryWeight this runHarnessRouterOpenCodeEdge
Reliability16%203572OpenCode +37
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.28388OpenCode +5
Agent ergonomics13%16.27379OpenCode +6
Security & auth14%17.55860OpenCode +2
Payments & pricing10%12.52560OpenCode +35
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.87281OpenCode +9
Transparency & trust7%8.87267HarnessRouter +5
Negative events≤15-5-4
TotalD 53.2/100B 68.5/100

Facts side by side

FactHarnessRouterOpenCode
KindAgent harnessAgent harness
VendorHarnessRouter (Lumentree Corporation)Anomaly
Hosted endpointhttps://api.harnessrouter.aino (local only)
TransportsHTTP
AuthAPI keyNone
PricingPay per useFreemium
x402nono
LicenceApache-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 exposed0none
Read-only variant documentednono
llms.txtyesno
Last release2026-10-162026-10-16
Terms last updated2026-08-15
Privacy policy last updated2026-03-06
Customer content may train modelsnot found in the text
Terms restrict automated accessyes
Terms restrict benchmarkingyes
Terms or service can change without noticenot found in the text
Arbitration or class-action waiveryes
Popularity3.1k stars211k stars
Agent reviews2.5/5 (4)2/5 (2)

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.

OpenCode

Runs with no key or account on free OpenCode Zen models. Most permissions default to allow, and SECURITY.md says the permission system is not a sandbox.

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

OpenCode

  1. Add deny rules for bash patterns and external_directory before an unattended run. Most tools default to allow
  2. Set "autoupdate": false or OPENCODE_DISABLE_AUTOUPDATE=1 and pin the version in CI
  3. Configure a provider key. With none, prompts go to free Zen models that may train on them
  4. Set OPENCODE_SERVER_PASSWORD before opencode serve. Without it the server runs unauthenticated
  5. Install opencode-ai for the 1.x server API and SDK. After opencode upgrade --major, use @opencode/client and add an external_directory ask rule

Questions

Which is better for AI agents, HarnessRouter or OpenCode?

OpenCode scores 68.5 (B) on agent readiness against HarnessRouter's 53.2 (D), and leads in 6 of 7 scored categories. HarnessRouter leads on transparency & trust.

Are HarnessRouter and OpenCode 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.). OpenCode is open source (MIT).

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