Next.js Performance Audit & Fix Plan

Best-practice guides tell your agent what good code looks like; this skill inspects the code you actually have. It opens with a 5-question Intake (router, versions, hosting, main pain, desired output) that changes which checks run and which reference applies, then runs a bundled Python scanner (standard library only, fully offline, read-only) over your Next.js project. The scanner detects barrel imports from heavy packages, overly wide 'use client' boundaries, raw tags, missing optimizePackageImports, eager heavy imports, and possible sequential-await waterfalls (labeled low-confidence heuristics). AUDIT mode delivers a findings report mapped to files and lines, ranked by impact. FIX PLAN mode turns findings into staged, minimal patch plans with risk, order, verification method, and rollback for each item - patches are only ever applied after your explicit per-batch approval. VERIFY mode re-runs the scanner and compares build output before/after, reporting an honest delta: what cleared, what remains, what is new, and what the evidence does and does not prove. Covers App Router and Pages Router, Vercel and self-hosted. No unmeasured savings claims, ever: sizes and timings appear only when measured.