Use when performance requirements exist, when you suspect performance regressions, or when Core Web Vitals or load times need improvement. Use when profiling reveals bottlenecks that need fixing.
Collected from public GitHub. Every version is saved exactly as it was and never changes. Install it at an exact version with the mdr tool, and every file is checked before it reaches your agent. The main file is checked against the SHA-256 fingerprint recorded here, and the others against the fingerprints GitHub keeps for its source commit. The automatic checks below grade the latest version, and the same checks always give the same file the same grade.
What the file says
# Performance Optimization
## Overview
Measure before optimizing. Performance work without measurement is guessing — and guessing leads to premature optimization that adds complexity without improving what matters. Profile first, identify the actual bottleneck, fix it, measure again. Optimize only what measurements prove matters.
## When to Use
- Performance requirements exist in the spec (load time budgets, response time SLAs)
- Users or monitoring report slow behavior
- Core Web Vitals scores are below thresholds
- You suspect a change introduced a regression
- Building features that handle large datasets or high traffic
**When NOT to use:** Don't optimize before you have evidence of a problem. Premature optimization adds complexity that costs more than the performance it gains.
## Core Web Vitals Targets
| Metric | Good | Needs Improvement | Poor |
|--------|------|-------------------|------|
| **LCP** (Largest Contentful Paint) | ≤ 2.5s | ≤ 4.0s | > 4.0s |
| **INP** (Interaction to Next Paint) | ≤ 200ms | ≤ 500ms | > 500ms |
| **CLS** (Cumulative Layout Shift) | ≤ 0.1 | ≤ 0.25 | > 0.25 |
## The Optimization Workflow
```
1. MEASURE → Establish baseline with real data
…
The line at the top of this page pins the label git:20260215.46f377a, which is what most people want. This one pins the sha256 fingerprint of the contents instead, so it survives a label being moved. Either way the exact version is written to mdr.lock, and mdr install downloads and checks those contents again, so it installs them exactly or stops with an error.
GET https://markdownregistry.com/api/v1/artifacts/art_js254jsspgmyvyvx
GET https://markdownregistry.com/api/v1/resolve?ref=lll0k0lad/agent-skills/performance-optimization
GET https://markdownregistry.com/api/v1/blob/fa8fdc842d28d7ba0842ba34aa371a7735f6869ea78f05fb0977893511f19062
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lll0k0lad/agent-skills · skills/api-and-interface-design/SKILL.md · Use when designing APIs, module boundaries, or any public interface. Use when creating REST or GraphQL endpoints…
lll0k0lad/agent-skills · skills/browser-testing-with-devtools/SKILL.md · Use when building or debugging anything that runs in a browser. Use when you need to inspect the DOM, capture console…
lll0k0lad/agent-skills · skills/ci-cd-and-automation/SKILL.md · Use when setting up or modifying build and deployment pipelines. Use when you need to automate quality gates, configure…
lll0k0lad/agent-skills · skills/code-review-and-quality/SKILL.md · Use before merging any change. Use when reviewing code written by yourself, another agent, or a human. Use when you…
lll0k0lad/agent-skills · skills/context-engineering/SKILL.md · Use when starting a new session, when agent output quality degrades, when switching between tasks, or when you need to…
lll0k0lad/agent-skills · skills/debugging-and-error-recovery/SKILL.md · Use when tests fail, builds break, behavior doesn't match expectations, or you encounter any unexpected error. Use when…
lll0k0lad/agent-skills · skills/documentation-and-adrs/SKILL.md · Use when making architectural decisions, changing public APIs, shipping features, or when you need to record context…
lll0k0lad/agent-skills · skills/frontend-ui-engineering/SKILL.md · Use when building or modifying user-facing interfaces. Use when creating components, implementing layouts, managing…
lll0k0lad/agent-skills · skills/git-workflow-and-versioning/SKILL.md · Use when making any code change. Use when committing, branching, resolving conflicts, or when you need to organize work…
lll0k0lad/agent-skills · skills/idea-refine/SKILL.md · Refine ideas through structured divergent and convergent thinking. Use "idea-refine" or "ideate" to trigger.
addyosmani/agent-skills · skills/performance-optimization/SKILL.md · Optimizes application performance across frontend, backend, queries, and databases. Use when performance requirements…
gamedev-skills/awesome-gamedev-agent-skills · skills/disciplines/performance-optimization/SKILL.md · Find and fix game performance problems methodically — measure with the engine profiler first, reason about the…
ukanwat/overtime · .claude/skills/performance-optimization/SKILL.md · Find and fix game performance problems methodically — measure with the engine profiler first, reason about the…
mindrally/skills · performance-optimization/SKILL.md · Performance optimization guidelines for web development including server-side rendering, CSS best practices, and…
shashankswe2020-ux/whoop-mcp · .github/skills/performance-optimization/SKILL.md · Optimizes application performance. Use when performance requirements exist, when you suspect performance regressions…
