What problem does it solve? When a Store-based application recomputes selectors too often or runs slowly, developers lack visibility into why. This Skill guides agents through enabling and interpreting the opt-in selector tracing diagnostics of the themis Store families, turning recomputation, invalidation, cache, and duration data into evidence for a performance diagnosis. ## Core Features & Use Cases - Trace configuration: Configure the flat traceSelectors constructor object for Store, ReactStore, or StreamingStore, choosing the smallest event-category set (execution, cache, invalidation, arguments, results, cadence) that answers the question. - Aggregate interpretation: Read [themis] selector trace summary console rows and lifetime getSelectorTraceSummary() snapshots, including duration aggregates, bounded p95, cache hit ratios, and fixed invalidation labels. - Privacy-safe diagnosis: Diagnose using callback source identity, counts, and durations only, since traces never expose selector arguments, results, or state values. - Use Case: A Svelte view re-renders excessively. Enable execution and invalidation tracing, reproduce the interaction after init(), and compare recomputation counts against invalidation reason labels to find the unstable selector input. ## Quick Start Enable selector tracing on my Store with execution and invalidation categories, then help me interpret the trace summary output to find why my selector keeps recomputing.
