battle-tested-patterns

Use when a developer wants to apply a low-level, systems, or concurrency design pattern in their own code, drawing on the Battle-Tested Patterns catalog of 46 production-proven patterns. Triggers three ways: they name a pattern (ring buffer, circuit breaker, actor model, LRU cache, rate limiter, trie, bloom filter, WAL, semaphore, ...); they describe a problem one solves without naming it (fixed-size buffer that overwrites the oldest entry, cascading failures across services, throttling requests, deduplicating identical strings, ordering events without wall-clock time, snapshot isolation, prefix search, set membership without storing every key, ...); or they ask which pattern fits a problem or how two related patterns differ.

Use when reviewing or auditing an existing codebase against production-proven implementation patterns — checking whether the patterns it already implements (actor model, rate limiter, circuit breaker, LRU cache, write-ahead log, semaphore, ...) actually honor the canonical invariants, whether any are mislabeled (a "semaphore" that is really a mutex; an "MVCC" that keeps one version), whether any diverge from the reference, and which catalog patterns are absent. Triggers on "audit our architecture against best practices", "do we implement X correctly", "are our patterns right", "pattern conformance", "is this really a <pattern>?". This grades patterns already present; its companion adopt-pattern adds new ones.

Structured debugging loop for exercise tests or build failures. Reproduce → isolate → hypothesize → fix → verify.

Guided workflow to create a new pattern following the project template and quality standards. Walks through topic validation, source verification, implementation, exercises, challenge questions, and bilingual docs.

Verify all production proof source links in pattern documents. Run automated checks for HTTP status, format, SHA permanence, and line-range content accuracy.