# Audit Feature Interaction > Analyze feature interaction pairs and triples for concurrent defects Use when this capability is needed. - Skill: `tomevault-io/audit-feature-interaction` (Agent Skill, multi-file: 2 files) - Install (CLI): `npx skillmds@latest add tomevault-io/audit-feature-interaction` - Raw SKILL.md: https://api.skillmd.com/api/skills/tomevault-io/audit-feature-interaction/raw - Safety review: pending (external: skill-scanner PASS, skillspector PASS) - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: Security - Author: tomevault-io (https://skillmd.com/u/tomevault-io) - Updated: 2026-09-17 - Page: https://skillmd.com/skills/tomevault-io/audit-feature-interaction --- Analyze the cache for defects arising from multiple features operating simultaneously on the same entry. Assume at least one feature interaction bug exists. If your analysis yields zero findings, re-examine the top-priority pairs below — explain specifically why no interleaving produces a bug. Priority ranking (from confirmed historical bugs): 1. **Refresh + expiration** (D+B) — most-bugged interaction historically 2. **Reference collection + any feature** (C+*) — value reference visibility 3. **Async completion + any feature** (F+*) — future lifecycle edge cases 4. **Eviction + weight change** (A+H) — counter drift during transitions Features: A. Eviction (size/weight limit exceeded) B. Expiration (afterAccess, afterWrite, variable) C. Reference collection (weak key, weak value, soft value GC) D. Refresh (automatic reload) E. Loading (CacheLoader / computeIfAbsent) F. Async completion (CompletableFuture values) G. Listener notification (removal listener, eviction listener) H. Weight change (Weigher returning different weight for new value) For each pair (A,B), (A,C), ..., (G,H) — 28 pairs total: 1. Can both features trigger simultaneously on the same entry? 2. If yes, construct the most adversarial interleaving. 3. Trace step-by-step: correct processing? notifications? final state? cleanup? After all pairs, identify highest-risk TRIPLE interactions: - Eviction + expiration + listener exception - Refresh + async completion + GC collection - Weight change + eviction + compute High-risk pairwise combinations: - Eviction during refresh (entry evicted while refreshing) - Expiration during compute (entry expires mid-computation) - GC during async completion (future completes after weak ref collected) - Weight change during eviction - Listener exception during any other feature For each defect: state the features involved, provide the interleaving, state the incorrect behavior. --- > Source: [ben-manes/caffeine](https://github.com/ben-manes/caffeine) — distributed by [TomeVault](https://tomevault.io).