# Performance > Performance - Core Web Vitals, bundle size. Use when optimizing speed. Use when this capability is needed. - Skill: `tomevault-io/performance` (Agent Skill, multi-file: 2 files) - Install (CLI): `npx skillmds@latest add tomevault-io/performance` - Raw SKILL.md: https://api.skillmd.com/api/skills/tomevault-io/performance/raw - Safety review: pending (external: skill-scanner PASS, skillspector PASS) - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: Coding & Dev Tools - Author: tomevault-io (https://skillmd.com/u/tomevault-io) - Updated: 2026-09-17 - Page: https://skillmd.com/skills/tomevault-io/performance --- # Performance Guideline ## Tech Stack * **Framework**: Next.js (SSR/ISR/Static) * **Platform**: Vercel * **Tooling**: Bun ## Non-Negotiables * Core Web Vitals must meet thresholds (LCP < 2.5s, CLS < 0.1, INP < 200ms) * Performance regressions must be detectable ## Context Performance is a feature. Slow products feel broken, even when they're correct. Users don't read loading spinners — they leave. Every 100ms of latency costs engagement. Don't just measure — understand. Where does time go? What's blocking the critical path? What would make the product feel instant? Sometimes small architectural changes have bigger impact than optimization. ## Driving Questions * What makes the product feel slow to users? * Where are the biggest bottlenecks in the critical user journeys? * What's in the critical rendering path that shouldn't be? * How large is the JavaScript bundle, and what's bloating it? * What database queries are slow, and why? * If we could make one thing 10x faster, what would have the most impact? --- > Converted and distributed by [TomeVault](https://tomevault.io/claim/sylphxai) — claim your Tome and manage your conversions.