fuzz-before-you-claim-donelisted

# Fuzz before you claim "done" ## Purpose A hand-picked test list is a mirror: it verifies the cases its author imagined, and the author of the tests is usually the author of the change. In someone else's repo that gap lands on the maintainer — the reviewer becomes your fuzzer. A seeded property sweep is the cheapest adversarial reviewer you can hire before the human one: randomized structures, deterministic per seed, checked against *invariants* ("no writes lost", "exactly once", "resume equals uninterrupted") rather than expected outputs. When it fails, the seed is the whole repro. ## When to use - Any change to execution semantics: scheduling, barriers/joins, retries, caching, interrupts/resume, checkpointing — anything where inputs combine. - Before writing "verified" / "all cases covered" in a PR body or a handoff. - When your deterministic suite is green and you notice every test was written by the same mind that wrote the code. ## When NOT to use Pure data transforms with enumerable inputs — a table-driven test is clearer. And don't ship the 10,000-seed run in CI: sweep large once, commit a small seeded subset, record the large run's result where the reviewer can see it. Two adjacent adversaries answer different doubts, and a fuzz run answers neither: [red-team-your-own-diff](../red-team-your-own-diff/SKILL.md) attacks the diff with a named reviewer's own recorded rules, and [run-the-bots-review-before-it-does](../run-the-bots-review-before-it-does/SKILL.md)