harness-validator

harness-validator is a skill for Claude Code from mathiasbourgoin/roster. It costs 25 tokens per session (1,092 once invoked), scanned A, original, MIT.

A checker for the project's knowledge-base harness: the files, rules, audit helpers, and connections that support its coding checks.

In plain words
What is it for?
Use it to verify the knowledge-base index and core files, check auditor installations, and confirm optional specification checks are configured correctly.
Why use it?
It finds missing files, invalid metadata, absent auditors, and broken setup links that could make the harness unreliable.

Skill for Claude Code

Written for Claude Code: when-to-use in frontmatter. Also seen: reads .claude/ paths; mentions CLAUDE.md; installed under .agents/ (shared by several agents).

Good fit Use it to verify the knowledge-base index and core files, check auditor installations, and confirm optional specification checks are configured correctly.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/mathiasbourgoin/roster/harness-validator
Install

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.

Any agent
npx skills add mathiasbourgoin/roster --skill harness-validator
Clone the repo
git clone --depth 1 https://github.com/mathiasbourgoin/roster

Made for: Claude Code.

Wrote 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.

agentmods badge for harness-validator

README.md
[![agentmods](https://agentmods.dev/badge/skills/mathiasbourgoin/roster/harness-validator.svg)](https://agentmods.dev/skills/mathiasbourgoin/roster/harness-validator)
Your own site
<a href="https://agentmods.dev/skills/mathiasbourgoin/roster/harness-validator"><img src="https://agentmods.dev/badge/skills/mathiasbourgoin/roster/harness-validator.svg" alt="Measured on agentmods" height="20"></a>
Per session 25 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,092 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00025 $0.01092
Opus 5 $0.00013 $0.00546
Sonnet 5 $0.00005 $0.00218
Haiku 4.5 $0.00003 $0.00109

Measured 8d ago against content hash 07193a6a73d9, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

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 8d 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.

.agents/skills/harness-validator/SKILL.md · 118 lines

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.md exists 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-updated frontmatter.
  • 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 required
    • code-quality-auditor.md — always required
    • harness-validator.md — always required (self-referential check)
    • spec-compliance-auditor.md — required only if specs/ 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 or AGENTS.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.

Read the full file on GitHub · 118 lines

Files

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.

Changes

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.

  1. 8d ago First seen · 118 lines · 25 tokens per session scan A 07193a6a73d9

Subscribe to this mod's changes

harness-validator is a skill published in the GitHub repository mathiasbourgoin/roster (2 stars, last pushed 2d ago), licensed MIT. It adds 25 tokens to every session and 1,092 once invoked, about $0.0001 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 2026-08-31.

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