What problem does it solve? Local Next.js dev servers can exhibit high CPU usage, excessive memory consumption, missing styles, and repeated route renders, and developers often waste time making speculative code edits instead of profiling first. This Skill enforces a profile-first workflow to identify the real root cause before touching UI code. ## Core Features & Use Cases - Standardized Profiling: Captures a profile bundle via make dev-profile-next and inspects live diagnostics with lsof, sample, footprint, and vmmap. - Failure Mode Diagnosis: Provides decision rules for common issues such as health probes hitting / instead of /health.txt, wrong turbopack.root, missing allowedDevOrigins, broken Tailwind @source scanning, and .next manifest corruption. - Use Case: When Activity Monitor shows a hot next-server process, use this Skill to compare footprint and vmmap output against V8 counters to determine whether the memory is native Turbopack/SWC footprint rather than a React leak. ## Quick Start Ask the agent to profile the Next.js dev server and diagnose why it is using high CPU and memory before making any code changes.