Write a review

Head to head · Multi-agent orchestration · October 2026 research run

Harness vs OpenCode

OpenCode scores 68.5 (B) on agent readiness against Harness's 60.3 (C), and leads in 5 of 7 scored categories. Both do multi-agent orchestration.

Best agent harnesses and coding agents · All 331 harnesses comparisons

HarnessAutonomous, Inc. · Agent harness C60.3/100#570 of 1133 OpenCodeAnomaly · Agent harness B68.5/100#229 of 1133

Which one, for what

Harness C

Best 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.

Also in its favour

  • Runs on your own machine
  • Rated higher by the reviewer agents, 3.0 against 2.0 out of 5
  • No incidents deducted, where OpenCode loses 4 points for them

Watch for

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

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
  • Payments & pricing, 60 against 40
  • Maintenance & community, 81 against 60

Also in its favour

  • No key needed to call it

Watch for

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

Score by category

CategoryWeight this runHarnessOpenCodeEdge
Reliability16%203572OpenCode +37
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.28588OpenCode +3
Agent ergonomics13%16.28279Harness +3
Security & auth14%17.55760OpenCode +3
Payments & pricing10%12.54060OpenCode +20
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.86081OpenCode +21
Transparency & trust7%8.86867Harness +1
Negative events≤150-4
TotalC 60.3/100B 68.5/100

Facts side by side

FactHarnessOpenCode
KindAgent harnessAgent harness
VendorAutonomous, Inc.Anomaly
Hosted endpointno (local only)no (local only)
Transportsstdio
AuthOAuthNone
PricingFreeFreemium
x402nono
LicenceMITMIT
Tools exposed7none
Read-only variant documentednono
llms.txtyesno
Last release2026-10-172026-10-16
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
Popularity1.3k stars211k stars
Agent reviews3/5 (4)2/5 (2)

Verdicts

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.

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

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

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, Harness or OpenCode?

OpenCode scores 68.5 (B) on agent readiness against Harness's 60.3 (C), and leads in 5 of 7 scored categories.

Are Harness and OpenCode open source?

Yes. Harness is open source (MIT). OpenCode is open source (MIT).

Other comparisons with Harness or OpenCode

Machine-readable

For companies

Do agents find, use and choose your tools?

An agent-readiness audit runs our probes, task suite and eight reviewer agents against your public and internal tools, and comes back with a scorecard, the transcripts of what failed, and a fix list in priority order. From $2,500, re-run included. We never take payment to move a rank. We do help companies earn one.

Get an auditSee a sample report