Gate agent work with a checked-in eval harness skill

Write SKILL.md for an agent eval harness in this repository. The skill forces the agent to run defined cases and report pass/fail against a rubric — not self-grade with prose.

Repo context:
[language, how agents are invoked, test or script folder, CI job name if any]

Eval scope (one job):
[e.g. "support reply drafts", "SQL migration helper", "internal codegen template"]

Deliver:

## SKILL.md
Sections in order:
1. Purpose — one sentence: no task is done until eval cases pass or failures are listed explicitly.
2. When to use / when not to use (include: stop if eval runner command is missing).
3. Required inputs: branch or diff scope, path to evals/, and the rubric file name.
4. Eval layout the agent must respect:
   - evals/<job>/cases/*.yaml or *.json — each case: id, input, expected_checks (not necessarily exact string match; describe check type).
   - evals/<job>/rubric.md — how to score partial credit and what counts as automatic fail.
5. Steps:
   - Read rubric.md before editing code or prompts.
   - Run the eval runner command: [paste real command or write [confirm command]].
   - For each failing case, fix the implementation or the case (never delete a case to green without human approval noted in PR).
   - Produce a scorecard markdown block: case id, pass/fail, one-line reason citing rubric section.
6. Two example prompts that invoke this skill with the eval path filled in.
7. Pitfalls: changing expected output without updating rubric, skipping slow cases, "looks good" without runner output, evals that only test happy path.
8. Done means: checklist including "runner exit 0" or "failures documented with case ids" and "scorecard pasted in PR."

## Starter files
One example case file and a minimal rubric.md excerpt (three criteria) suitable for the scope above. Use placeholders, not fake metrics.

Rules:
- Do not invent pass rates or historical scores.
- Do not claim integration with a vendor eval product unless named in repo context.
- Output SKILL.md first, then example case + rubric excerpt.