skills/observability/performance-profiling/SKILL.md
Performance profiling principles. Measurement, analysis, and optimization techniques.
npx skillsauth add bereniketech/claude_kit performance-profilingInstall this skill globally with one command. Works with Claude Code, Cursor, and Windsurf.
3 of 9 scanners reported clean
Some scanners were skipped, did not run, or reported a non-clean status. Review each row below.
Measure, analyze, optimize - in that order.
Execute these for automated profiling:
| Script | Purpose | Usage |
|--------|---------|-------|
| scripts/lighthouse_audit.py | Lighthouse performance audit | python scripts/lighthouse_audit.py https://example.com |
| Metric | Good | Poor | Measures | |--------|------|------|----------| | LCP | < 2.5s | > 4.0s | Loading | | INP | < 200ms | > 500ms | Interactivity | | CLS | < 0.1 | > 0.25 | Stability |
| Stage | Tool | |-------|------| | Development | Local Lighthouse | | CI/CD | Lighthouse CI | | Production | RUM (Real User Monitoring) |
1. BASELINE → Measure current state
2. IDENTIFY → Find the bottleneck
3. FIX → Make targeted change
4. VALIDATE → Confirm improvement
| Problem | Tool | |---------|------| | Page load | Lighthouse | | Bundle size | Bundle analyzer | | Runtime | DevTools Performance | | Memory | DevTools Memory | | Network | DevTools Network |
| Issue | Indicator | |-------|-----------| | Large dependencies | Top of bundle | | Duplicate code | Multiple chunks | | Unused code | Low coverage | | Missing splits | Single large chunk |
| Finding | Action | |---------|--------| | Big library | Import specific modules | | Duplicate deps | Dedupe, update versions | | Route in main | Code split | | Unused exports | Tree shake |
| Pattern | Meaning | |---------|---------| | Long tasks (>50ms) | UI blocking | | Many small tasks | Possible batching opportunity | | Layout/paint | Rendering bottleneck | | Script | JavaScript execution |
| Pattern | Meaning | |---------|---------| | Growing heap | Possible leak | | Large retained | Check references | | Detached DOM | Not cleaned up |
| Symptom | Likely Cause | |---------|--------------| | Slow initial load | Large JS, render blocking | | Slow interactions | Heavy event handlers | | Jank during scroll | Layout thrashing | | Growing memory | Leaks, retained refs |
| Priority | Action | Impact | |----------|--------|--------| | 1 | Enable compression | High | | 2 | Lazy load images | High | | 3 | Code split routes | High | | 4 | Cache static assets | Medium | | 5 | Optimize images | Medium |
| ❌ Don't | ✅ Do | |----------|-------| | Guess at problems | Profile first | | Micro-optimize | Fix biggest issue | | Optimize early | Optimize when needed | | Ignore real users | Use RUM data |
Remember: The fastest code is code that doesn't run. Remove before optimizing.
This skill is applicable to execute the workflow or actions described in the overview.
testing
AUTHORIZED USE ONLY: This skill contains dual-use security techniques. Before proceeding with any bypass or analysis: > 1.
testing
Provide comprehensive techniques for attacking Microsoft Active Directory environments. Covers reconnaissance, credential harvesting, Kerberos attacks, lateral movement, privilege escalation, and domain dominance for red team operations and penetration testing.
development
Detects missing zeroization of sensitive data in source code and identifies zeroization removed by compiler optimizations, with assembly-level analysis, and control-flow verification. Use for auditing C/C++/Rust code handling secrets, keys, passwords, or other sensitive data.
development
Comprehensive guide to auditing web content against WCAG 2.2 guidelines with actionable remediation strategies.