harness:certify

A repeatability check for an evolved agent that runs its evaluation three times and summarizes the scores.

In plain words
What is it for?
Use it to calculate the mean, standard deviation, score range, and a stability verdict for the current agent.
Why use it?
A single evaluation can be unusually high or low, making it hard to know whether an improvement is reliable.

Skill for Claude CodeCodex

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.

agentmods
npx agentmods add skills/raphaelchristi/harness-evolver/certify
Any agent
npx skills add raphaelchristi/harness-evolver --skill certify
Clone the repo
git clone --depth 1 https://github.com/raphaelchristi/harness-evolver

Made for: Claude Code, Codex.

Per session 34 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 547 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00034 $0.00547
Opus 5 $0.00017 $0.00273
Sonnet 5 $0.00007 $0.00109
Haiku 4.5 $0.00003 $0.00055

Measured 2d ago against content hash 6dbbe7635f6d, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

harness:certify 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 2d 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.

skills/certify/SKILL.md · 64 lines

What it actually says

/harness:certify

Verify score stability by running evaluation multiple times and reporting statistical confidence.

Resolve Tool Path

TOOLS="${EVOLVER_TOOLS:-$([ -d ".evolver/tools" ] && echo ".evolver/tools" || echo "$HOME/.evolver/tools")}"
EVOLVER_PY="${EVOLVER_PY:-$([ -f "$HOME/.evolver/venv/bin/python" ] && echo "$HOME/.evolver/venv/bin/python" || echo "python3")}"

What To Do

Read .evolver.json to get the best experiment and dataset.

Run evaluation 3 times on the current code (not a worktree — the best code is already merged):

for i in 1 2 3; do
    $EVOLVER_PY $TOOLS/run_eval.py \
        --config .evolver.json \
        --worktree-path "." \
        --experiment-prefix "certify-run-$i"
done

After all 3 runs complete, read results and compute statistics:

$EVOLVER_PY $TOOLS/read_results.py --experiments "certify-run-1-{suffix},certify-run-2-{suffix},certify-run-3-{suffix}" --config .evolver.json --format summary

Calculate mean and standard deviation from the 3 combined_scores.

Report

CERTIFICATION REPORT
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
Runs:  3
Mean:  {mean:.3f}
Std:   {std:.3f}
Range: {min:.3f} — {max:.3f}

Verdict: {STABLE|UNSTABLE}

STABLE (std < 0.05): Score is reliable. The agent performs consistently.

MARGINAL (0.05 <= std < 0.10): Score varies moderately. Consider adding rubrics to reduce judge variance.

UNSTABLE (std >= 0.10): Score is unreliable. The LLM judge interprets criteria differently across runs. Add few-shot examples or tighter rubrics.

After Certification

If STABLE: suggest /harness:deploy to finalize. If UNSTABLE: suggest adding rubrics to dataset examples, or running /harness:evolve with heavy mode for more thorough evaluation.

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. 2d ago First seen · 64 lines · 34 tokens per session scan A 6dbbe7635f6d

Subscribe to this mod's changes

harness:certify is a skill published in the GitHub repository raphaelchristi/harness-evolver (49 stars, last pushed 4mo ago), licensed MIT. It adds 34 tokens to every session and 547 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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