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 skills add mathiasbourgoin/roster --skill harness-validatorgit clone --depth 1 https://github.com/mathiasbourgoin/rosterWrote 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/skills/mathiasbourgoin/roster/harness-validator)<a href="https://agentmods.dev/skills/mathiasbourgoin/roster/harness-validator"><img src="https://agentmods.dev/badge/skills/mathiasbourgoin/roster/harness-validator/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/mathiasbourgoin/roster/harness-validator"><img src="https://agentmods.dev/badge/skills/mathiasbourgoin/roster/harness-validator.svg" alt="Reviewed on agentmods" width="80" 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 5.1 | $0.00020 | $0.01087 |
| Opus 5.5 | $0.00008 | $0.00435 |
| Sonnet 5.5 | $0.00004 | $0.00217 |
| Haiku 4.5 | $0.00002 | $0.00109 |
Grade A, and why
harness-validator 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 1mo 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 — 118 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Harness Validator
Verify the integrity of the knowledge base harness: KB structure, installed auditors, rule coherence, hook configuration, and feedback loop wiring.
Steps
1. Check: KB Exists and Has Valid Structure
- Verify
kb/index.mdexists and lists all KB files. - Verify core files exist:
spec.md,properties.md,glossary.md. - For each file in the index, confirm it actually exists on disk.
- Check each KB file has
last-updatedfrontmatter. - Flag missing core files as Critical. Flag missing indexed files as Warning.
2. Check: Auditor Skills Installed
- Verify each required auditor skill exists in
skills/kb/:ambiguity-auditor.md— always requiredcode-quality-auditor.md— always requiredharness-validator.md— always required (self-referential check)spec-compliance-auditor.md— required only ifspecs/directory exists in project root[ -d specs ] && echo "spec-compliance required" || echo "spec-compliance optional"
- Check each has valid frontmatter with
description. - Verify installed copies exist in
.harness/skills/and any Claude compatibility copies in.claude/commands/(if install has been run). - Flag missing auditors as Critical.
3. Check: Rules Coherence
- Read
.harness/rules/first, then.claude/rules/compatibility copies if present. - Read agent definitions (e.g.,
agents/directory orAGENTS.md). - Verify: rules reference KB files that exist, agent instructions don't contradict rules, no orphaned rules referencing deleted agents.
- Flag contradictions as Critical. Flag orphaned rules as Warning.
4. Check: Hook Configuration
- Read
.harness/hooks/and any runtime hook projection such as.claude/settings.json. - Verify hooks don't block tools that agents need (e.g., a pre-commit hook that blocks Bash would break all agents).
- Check that hook commands reference valid scripts/paths.
- Flag blocking hooks as Critical. Flag missing expected hooks as Info.
What ships with it
1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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.
- 1mo ago Changed · -5 tokens per session 7d1ab419fa4b
- 2mo ago First seen · 118 lines · 25 tokens per session scan A 07193a6a73d9
harness-validator is a skill published in the GitHub repository mathiasbourgoin/roster (2 stars, last pushed 6d ago), licensed MIT. It adds 20 tokens to every session and 1,087 once invoked, about $0.0001 per session on Opus 5.5. 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 2026-08-31.
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