What problem does it solve? Reviewing pull requests that add or modify .NET background services is error-prone: a single unhandled exception in ExecuteAsync can stop the entire host, cancellation tokens get swallowed by per-item catches, and idempotency claims often hide TOCTOU races at the store layer. This Skill provides a systematic checklist so reviewers catch these defects with file:line evidence instead of gut feel. ## Core Features & Use Cases - Nine-point review checklist: Covers ExecuteAsync try/catch coverage, cancellation filtering, PeriodicTimer semantics, store-level idempotency vs TOCTOU, settings-channel parsing, LoggerMessage EventId invariants, and test fidelity for loops. - Claims-vs-code verdict table: Converts every PR-body safety claim (off-by-default, never-mutates, idempotent, no-delete-path) into a HOLDS / HOLDS-with-caveat / FAILS verdict backed by grep evidence. - Severity calibration: Distinguishes MUST-FIX from SHOULD-FIX and NIT findings by comparing against same-repo precedent and pre-existing synchronous-path exposure. - Use Case: When a teammate opens a PR adding a background sync loop over a SQLite store, run this review to verify the interval re-read sits inside the try block, per-item catches filter OperationCanceledException, and the dedup claim survives a multi-process topology check. ## Quick Start Ask the agent to review the open pull request that adds a BackgroundService using the dotnet-hosted-service-review checklist and produce numbered findings with severity and file:line evidence.
