Recommendation-system engineering
Resolve constraints that change implementation: objective, QPS, P99, data/feature scale, freshness, consistency, runtime, deployment, availability, privacy, and cost.
Search the local PDF index and read cited pages. Keep 本书依据, repository convention, and engineering assumptions separate. Reuse runnable templates and label [MOCK] teaching substitutes.
Services require explicit contracts, timeouts, overload/degradation, observability, version consistency, rollback, and capacity. Models require objective, sampling, feature-time semantics, offline/online parity, complexity, and evaluation.
Run the changed path. Report 本书依据, 工程实现, 验证, and unresolved 待业务确认.


