# 9 Best Claude Skills for Performance Engineering

> Compare Claude skills for caching, Web Vitals, bundles, React renders, load tests, cold starts, CPU profiles, memory leaks, and prompt caches.

Choose a Claude performance skill from measured evidence: cache-policy-designer for freshness and origin load, web-vitals-optimizer for real-user browser metrics, bundle-analyzer and react-render-profiler for frontend cost, load-test-designer for capacity, and flamegraph or memory skills for runtime bottlenecks.

The best Claude performance skill depends on the evidence you have. A browser field metric, JavaScript bundle report, React trace, load-test curve, flamegraph, heap snapshot, and cold-start profile describe different systems. Asking Claude to “make it faster” before choosing the measurement invites speculative edits.

| Skill | Best for | Evidence | Main result |
| --- | --- | --- | --- |
| [cache-policy-designer](/skills/performance/cache-policy-designer) | Freshness and origin load | Data flow and cache behavior | Layered cache policy |
| [web-vitals-optimizer](/skills/performance/web-vitals-optimizer) | LCP, CLS, and INP | RUM/CrUX plus trace | Targeted browser fix |
| [bundle-analyzer](/skills/performance/bundle-analyzer) | Client JavaScript size | Build artifact report | Ranked size reductions |
| [react-render-profiler](/skills/performance/react-render-profiler) | Wasteful UI renders | React profiler trace | Render-path fix |
| [load-test-designer](/skills/performance/load-test-designer) | Throughput and saturation | Representative workload | Load-test plan |
| [cold-start-optimizer](/skills/performance/cold-start-optimizer) | Startup latency | Phase timing | Startup improvements |
| [flamegraph-analyzer](/skills/performance/flamegraph-analyzer) | CPU time | CPU profile | Hot-path diagnosis |
| [memory-leak-hunter](/skills/performance/memory-leak-hunter) | Growing memory | Heap snapshots | Retention-path diagnosis |
| [prompt-cache-optimizer](/skills/performance/prompt-cache-optimizer) | LLM prefix reuse | Token and latency data | Prompt-cache strategy |

## 1. cache-policy-designer: make caching correct

[cache-policy-designer](/skills/performance/cache-policy-designer) inventories the authoritative data, all cache layers, key dimensions, privacy boundary, freshness tolerance, invalidation events, stampede behavior, and outage semantics. It distinguishes browser or CDN headers from application and data caches instead of applying one TTL everywhere.

Use it before adding a cache and when users report stale or cross-tenant responses.

## 2. web-vitals-optimizer: improve real-user experience

[web-vitals-optimizer](/skills/performance/web-vitals-optimizer) anchors on p75 field LCP, CLS, and INP. It uses lab tooling to identify the element, shift, or long task responsible, applies one targeted change, and verifies the mechanism immediately while field data accumulates.

## 3. bundle-analyzer: find shipped JavaScript cost

[bundle-analyzer](/skills/performance/bundle-analyzer) measures built chunks, duplication, eager imports, large dependencies, polyfills, and route boundaries. It ranks reductions by bytes and user reach rather than recommending package removal without checking use.

## 4. react-render-profiler: explain render work

[react-render-profiler](/skills/performance/react-render-profiler) reads commit and component timing, prop or state changes, context fan-out, repeated calculations, and list behavior. It avoids reflexive memoization when the render is cheap or the dependency comparison costs more.

## 5. load-test-designer: find the capacity curve

[load-test-designer](/skills/performance/load-test-designer) models arrival rate, concurrency, user journeys, data variation, ramp, steady state, spikes, and recovery. It defines latency percentiles, error rate, throughput, saturation, and resource signals, then separates generator limits from system limits.

## 6. cold-start-optimizer: shorten initialization

[cold-start-optimizer](/skills/performance/cold-start-optimizer) decomposes startup into platform allocation, runtime bootstrap, imports, configuration, network connections, and application initialization. Optimize the dominant phase and check whether warm performance or correctness regresses.

## 7. flamegraph-analyzer: fix the widest CPU path

[flamegraph-analyzer](/skills/performance/flamegraph-analyzer) interprets width as sampled CPU time, follows stacks to the widest actionable leaf, and distinguishes useful work from framework, serialization, allocation, or lock overhead. Capture a representative workload before reading the graph.

## 8. memory-leak-hunter: locate retained growth

[memory-leak-hunter](/skills/performance/memory-leak-hunter) compares heap snapshots or allocation profiles across repeated cycles, identifies growing object classes, and traces retaining paths to roots. A high heap at one moment is not enough; a leak requires retained growth under a controlled workload.

## 9. prompt-cache-optimizer: reuse stable LLM prefixes

[prompt-cache-optimizer](/skills/performance/prompt-cache-optimizer) organizes stable instructions and reference context ahead of variable conversation content so provider caching can reuse prefix computation. It measures hit rate, cached tokens, latency, and cost without changing prompt behavior blindly.

## Recommended performance stack

For a web application, combine field experience, shipped code, runtime capacity, and cache correctness:

```bash
npx agentscamp add skills/web-vitals-optimizer
npx agentscamp add skills/bundle-analyzer
npx agentscamp add skills/load-test-designer
npx agentscamp add skills/cache-policy-designer
```

Every optimization report should state the baseline, workload, bottleneck evidence, exact change, post-change measurement, and tradeoffs. Without a comparable before-and-after result, the change is only a theory.

## Continue exploring

- [9 Best Claude Skills for Frontend Development](/guides/skills/best-claude-skills-for-frontend-development) — Compare Claude skills for accessibility, Web Vitals, React renders, bundles, localization, browser security, test data, tests, and caching.

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_Source: https://agentscamp.com/guides/skills/best-claude-skills-for-performance — Guide on AgentsCamp._