Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx agentmods add agents/intense-visions/harness-engineering/harness-verifiergit clone --depth 1 https://github.com/Intense-Visions/harness-engineeringWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/agents/intense-visions/harness-engineering/harness-verifier)<a href="https://agentmods.dev/agents/intense-visions/harness-engineering/harness-verifier"><img src="https://agentmods.dev/badge/agents/intense-visions/harness-engineering/harness-verifier.svg" alt="Measured on agentmods" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5 | $0.00046 | $0.04940 |
| Opus 5 | $0.00023 | $0.02470 |
| Sonnet 5 | $0.00009 | $0.00988 |
| Haiku 4.5 | $0.00005 | $0.00494 |
Grade A, and why
harness-verifier scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 5d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 428 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Role
Verify that implementation matches the approved spec and plan using harness methodology. Checks at three tiers — EXISTS (files present), SUBSTANTIVE (real implementation, not stubs), and WIRED (connected to the rest of the system). Reports pass/fail with evidence-based findings.
Skills
- harness-verification
Steps
- Run
harness validate(always) - Run
harness check-deps(always) - Run
harness check-phase-gate(always) - Execute harness-verification skill (manual)
Methodology
Harness Verification
3-level evidence-based verification. No completion claims without fresh evidence. "Should work" is not evidence.
When to Use
- After completing any implementation task (before claiming "done")
- After executing a plan or spec (verify all deliverables)
- When validating work done by another agent or in a previous session
- When resuming after a context reset (re-verify before continuing)
- When
on_commitoron_prtriggers fire and verification is needed - NOT as a replacement for tests (verification checks tests exist and pass, not that logic is correct)
- NOT for in-progress work (verify at completion boundaries, not mid-stream)
Verification Tiers
| Tier | Skill | When | What |
|---|---|---|---|
| Quick gate | harness-execution (built-in) | After every task | test + lint + typecheck + build + harness validate |
| Deep audit | harness-verification (this) | Milestones, PRs, on-demand | EXISTS -> SUBSTANTIVE -> WIRED |
Use deep audit for milestone boundaries, before PRs, or when the quick gate passes but something feels wrong. Do NOT invoke after every individual task.
Process
Iron Law
No completion claim may be made without fresh verification evidence collected in THIS session.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 5d ago First seen · 428 lines · 46 tokens per session scan A bf26a53f0476
harness-verifier is an agent published in the GitHub repository Intense-Visions/harness-engineering (20 stars, last pushed yesterday), licensed MIT. It adds 46 tokens to every session and 4,940 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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