CACHE_SHAPE_SINCE marks the last change that moved every cache key. The run service's periodic sweep clears cache_key on rows of runs created before it, which nothing can match any more. Their outputs stay. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01WgBfkm4rCmtd1T4vHWjEPx