Plan perf audit

Skill kensaurus/cursor-kenji/skills/plan-perf-audit

🦖Curated Cursor AI agent skills, slash commands, MCP configs, subagents & rules for full-stack dev — React 19, Next.js 15, Supabase, Tailwind v4, TypeScript

Install

npx -y skills add kensaurus/cursor-kenji --skill plan-perf-audit

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Measure-don't-guess performance audit across web, mobile, backend, and data layers — produces burndown and optimization plan with no fixes in this pass. No fabricated metrics; every issue needs a measured baseline or [NEEDS PROFILING]. Research-backed proposals for React (code-split, memo, react-window, startTransition), RN (Hermes, JSI, <2s cold start), data N+1/index work with EXPLAIN, and prevention via Lighthouse CI budgets + RUM. Mobile thresholds stricter than web CWV. Use when asked to "performance audit plan", "perf burndown", "measure before optimize", "bundle size audit", "LCP slow", "N+1 audit plan", "plan performance improvements", or "Core Web Vitals audit".

The file declares its own license as MIT. That is the author’s claim about this one file, and it is not the same thing as the license GitHub reports for the repository, which is listed with the other numbers below.

SKILL.md

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Performance Audit + Optimization Plan

Role: Senior performance engineer (web + mobile + backend/data).

Task: Profile the app, find performance issues across layers, plan fixes. Measure, don't guess. Audit & plan only — do not optimize in this pass.

This skill vs neighbors

Skill	Does
plan-perf-audit (this)	Plan with measured baselines
`audit-performance`	Audit + may optimize
`audit-bundle-size`	JS bundle focus + reduction
`backend-db-performance`	Query/index fixes (execution)
`mobile-rn-performance`	RN perf fixes (execution)

Loop: see docs/PLAN-LOOPS.md — after plan-test-coverage, parallel with plan-security-audit, before plan-docs-sync

⛔ Preservation Contract

Read references/preservation-contract.md. Acknowledge in output #1.

Hardest guardrail: no fix proposed without a measured baseline (or explicit [NEEDS PROFILING]).

References

File	Contents
`references/audit-scope.md`	Layers, methodology, measurement, research fixes
`references/output-templates.md`	Baselines, burndown, phased plan

Phase flow

1. Fingerprint stack (web/RN/API/Supabase)
2. Measure baselines per layer (no guessing)
3. Trace hot paths
4. Per-layer issue inventory
5. Burndown + phased optimization plan
6. Guardrails (budgets, Lighthouse CI, RUM)
7. Research citations

Optional browser: Lighthouse via playwright-cli. Read protocol-browser-anti-stall first.

Phase 1 — Measure first

Establish baselines before any fix proposal:

Layer	Tools
Web CWV	Lighthouse, `web-vitals`, RUM/Sentry
Bundle	`rollup-plugin-visualizer`, `@next/bundle-analyzer`
RN	Metro bundle report, cold start profiler
API	Sentry transactions, server logs
DB	Supabase advisors, `EXPLAIN ANALYZE`, slow query logs

Scope detail: references/audit-scope.md

Phase 2–4 — Hot paths + inventory

Prioritize highest-traffic screens, endpoints, queries. Tie each issue to path:line or query text.

Root-cause, not symptom. Quantify expected gain where possible.

Phase 5 — Burndown + plan

Template: references/output-templates.md

Phases: (1) P0 hot-path wins → (2) structural → (3) polish.

Prevention: performance budgets in CI, RUM for real users, re-measure after each fix.

Required output (in order)

Preservation-contract acknowledgment
Measured baselines per layer
Per-layer issue inventory
Burndown table (measured current + target + risk)
Optimization + enhancement plan, phased
Guardrails/tooling
Research notes + citations
Open questions / [NEEDS PROFILING] list

Rules

Plan only — do not optimize until approved.
Measure, don't guess. No fabricated numbers.
Optimizations preserve behavior + output.
Re-measure after fixes; keep before/after.