layer-engineering-standardslisted

# <LAYER/LANGUAGE> engineering standards > Keep each layer's standards scoped to that layer only. A schema specialist should not > carry frontend rules. A frontend specialist should not carry SQL index rules. Scope by > language/layer: do not trim content, split it. ## Severity model (shared across all layers) - `[BLOCKER]` — must fix before merge (correctness, security, data loss). - `[MAJOR]` — should fix (design, maintainability, missing tests). - `[MINOR]` — worth fixing (readability, small inefficiency). - `[NIT]` — optional (style, naming). ## Correctness & design - <e.g. layer boundaries respected; no business logic in the wrong layer> - <e.g. inputs validated at the boundary; failure modes handled> ## <Language-specific rules> - <e.g. async everywhere IO happens; cancellation honoured; no sync-over-async> - <e.g. nullability handled; disposal correct> - <e.g. for SQL: index coverage & selectivity; SARGable predicates; no N+1> ## Testing - <what must be tested at this layer, and how (unit / integration / behaviour)> - Test behaviour through public interfaces, not internals. ## Security & logging - No hardcoded secrets. Mask/pseudonymize sensitive identifiers in logs. - No logging of credentials, tokens, or raw PII. ## Compile/build correctness - The change must build and the relevant tests must pass before hand-off. ## Vendoring note If you have an authoritative in-house standard, vendor it here **verbatim** and pin it to a specific commit, so the skill matches