What problem does it solve? Debugging why Vercel-served pages are stale, uncached, or expensive is hard because cache outcomes span multiple layers (CDN, ISR, PPR) and the raw x-vercel-cache status alone cannot explain the cause. This Skill provides a systematic runbook for measuring cache hit rate, attributing misses and bypasses to specific reasons, and controlling ISR revalidation costs. ## Core Features & Use Cases - Cache hit rate analysis: Group vercel.request.count by cache_result, path_type, and route to find where MISS traffic concentrates, excluding BYPASS noise from the calculation. - Per-request diagnosis: Interpret the nine cacheReason values (cold, collapsed, error, draft_mode, prerender_bypass, crawler, stale_time, stale_tag, stale_error) and the three ppr_state values from vercel logs to explain individual request outcomes. - ISR cost control: Measure write units by route, path, and cache_tags to detect hot tags with large blast radius, then shift from time-based to on-demand tag revalidation. - Use Case: Your ISR bill spiked after a CMS webhook change. Use this Skill to group write units by cache_tags, discover a broad blogPost tag invalidating thousands of pages on every edit, and scope invalidation to blogPost:<id> instead. ## Quick Start Ask the agent to analyze why your Vercel site's cache hit rate is low and which routes are driving ISR write costs.
