---
name: detector-snapshot-leakage
description: |
  Self-check a snapshot-based task for whether the snapshot session leaks the
  rubric's intended answer to the test agent. `/create-snapshot` is meant to
  capture a failure mode the task tests recovery from — not extra context
  that hands the test agent a roadmap to the answer the rubric scores. Run
  this skill on your task before submission to catch leaks while you can
  still fix them.
allowed-tools: Bash, Read, Write
---

# Snapshot-leakage detector

This skill checks one of your tasks for snapshot leakage — the most common
failure mode for snapshot-based tasks, where the prior conversation in
`session.jsonl` already contains the answer the rubric is testing for, so the
test agent gets full credit by repeating something the snapshot handed them.

Read these before deciding:

1. `.claude/skills/_detector-worker-shell.md` — where to write the report and how to handle re-runs.
2. `.claude/skills/detector-snapshot-leakage/core.md` — what this detector looks for, the three shapes a leak can take, verdict enums, frontmatter/body schema.

Compose the report per the schema in `core.md` and write it per `_detector-worker-shell.md`.

## Acting on the verdict

- **`clear-leak`** or **`partial-leak`** — your snapshot is doing work the
  rubric expects the agent to do. The fix is usually to trim the snapshot
  (cut the assistant turns that articulate the answer) and replace them with
  prior conversation that sets up the *failure mode* without resolving it. Re-run
  this skill after editing to confirm the verdict moved to `clean`.
- **`clean`** — the snapshot stops short of giving the answer. Good.
- **`not-applicable`** — the snapshot or rubric is missing/empty. Either
  this isn't a snapshot task, or the rubric isn't drafted yet. Come back to
  this skill once both artifacts exist.