{"slug":"join-grain-guard","source_name":"join-grain-guard","name":"Join Grain & Fan-out Guard","description":"Reviews or writes a multi-table SQL join for grain and fan-out safety — confirms the join key is unique on one side before an aggregate, catches many-to-many row multiplication, spots a LEFT JOIN silently turned INNER by a WHERE on the right table, and states the grain of the result. Use when a query joins two or more tables and then sums, counts, or averages, or when a reported total looks inflated. Do NOT use for single-table queries, index/performance tuning (that is postgres-query-review), or ORM/query-builder API questions.","version":1,"lift":{"pass_rate_delta_pts":null,"pass_rate_pct":30.8,"total_cases":13,"passed_cases":4,"tokens_delta_pct":513.4,"turns_delta_pct":0,"verdict":"mixed","benchmark_model":"gemini-3.5-flash","grading_method":"judged","completed_at":"2026-07-10T09:07:23.767448+00:00"},"skill_score":0.9800995024875622,"benchmark_models":[{"model":"gemini-3.5-flash","headline":false,"delta_pts":null,"with_pass_pct":null,"without_pass_pct":null,"tokens_delta_pct":513.4,"turns_delta_pct":0,"total_cases":13,"cases_aggregated":13,"verdict":"mixed","never_hurt":true,"completed_at":"2026-07-10T09:07:23.767448+00:00","run_id":"d8bcc2da-90d9-4e9b-b5ad-0829e090e9a0","latest_attempt":{"id":"d8bcc2da-90d9-4e9b-b5ad-0829e090e9a0","runner_model":"gemini-3.5-flash","overall_verdict":"mixed","completed_at":"2026-07-10T09:07:23.767448+00:00","gate":"not_comparable"},"version_number":1,"is_latest_version":true,"gate":"not_comparable"}],"trust":{"skill_safety":"passed","safety_status":"clean","intent_verdict":"safe","content_status":"clean","indexable":false},"license":null,"install_count":0,"total_uses":688,"total_users":1,"manifest_hash":"995abe5f2e338c009da809979da37a14aca3d2e0c4d72f550400f4e4b384aa8c","install_name":"join-grain-guard","version_id":"6490bc22-2a5a-4d93-a18f-86276a0559d1","body_sha256":"28f42e368ba1d341642f0cb859311f4fda8b217d80b9e7802618c6e5e79ab51d","render_hash":"dd5ed118dbb0a21b83a857b1ea474825d0a1b6607017b418ba03491128a13f5b","raw_url":"https://app.decimal.ai/s/join-grain-guard/SKILL.md","scorecard_url":"https://app.decimal.ai/skills/join-grain-guard"}