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Analyze web and backend performance using Web Vitals, network timing, and Node.js metrics. Use when the user asks about page performance, load times, Core Web Vitals (LCP, CLS, INP), slow pages, backend bottlenecks, or SEO performance factors.
Codex または Claude でインストール この Prompt をコピーして Codex、Claude、または他のアシスタントに貼り付けると、Skill ページを確認してインストールできます。
SOC 職業分類に基づく
Test API integrations by mocking responses, intercepting requests, and monitoring network traffic. Use when the user wants to mock backend APIs, simulate errors, test offline behavior, intercept requests, or add authentication headers.
Automates browser interactions using Playwright for web testing, debugging, and automation. Use when the user needs to navigate websites, take screenshots, fill forms, click elements, extract page content (HTML/text), audit accessibility (ARIA/AX tree), measure Web Vitals performance, monitor console logs and HTTP requests, mock API responses, execute JavaScript in browser, inspect React components, compare UI with Figma designs, or perform non-blocking debugging with tracepoints, logpoints, and exception monitoring.
Automated browser testing, interaction automation, and form testing. Use when the user needs to test web pages, automate browser interactions, fill forms, test validation, run multi-step wizards, or test login/signup flows.
Debug web and Node.js applications using console inspection, network analysis, and non-blocking code debugging. Use when the user reports bugs, wants to debug JavaScript (browser or backend), inspect network requests, troubleshoot page/API issues, trace function calls, or monitor exceptions.
CLI for debugging Node.js backend processes with non-blocking inspection. Use when the user needs to connect to Node.js processes (by PID, name, Docker, or port), set tracepoints/logpoints/exceptionpoints, capture call stacks and local variables, or inspect console logs. Requires daemon; connect before other debug commands.
Monitor and debug web and Node.js applications using OpenTelemetry, console logs, network requests, and distributed tracing. Use when the user asks about distributed tracing, correlating frontend/backend requests, OpenTelemetry, Jaeger, or monitoring application behavior.
| name | performance-audit |
| description | Analyze web and backend performance using Web Vitals, network timing, and Node.js metrics. Use when the user asks about page performance, load times, Core Web Vitals (LCP, CLS, INP), slow pages, backend bottlenecks, or SEO performance factors. |
| allowed-tools | Bash(browser-devtools-cli:*), Bash(node-devtools-cli:*) |
Analyze web page performance using Web Vitals and network timing metrics.
This skill activates when:
browser-devtools-cli o11y get-web-vitals
browser-devtools-cli --json o11y get-web-vitals
browser-devtools-cli --json o11y get-web-vitals --wait-ms 3000
browser-devtools-cli --json o11y get-web-vitals --include-debug
browser-devtools-cli --json o11y get-http-requests
browser-devtools-cli --json o11y get-http-requests --resource-type script
browser-devtools-cli --json o11y get-http-requests --resource-type stylesheet
browser-devtools-cli --json o11y get-http-requests --status '{"min":400}'
browser-devtools-cli content take-screenshot --name "above-fold"
browser-devtools-cli content take-screenshot --name "full-page" --full-page
| Metric | Good | Needs Work | Poor |
|---|---|---|---|
| LCP | ≤2.5s | 2.5-4s | >4s |
| INP | ≤200ms | 200-500ms | >500ms |
| CLS | ≤0.1 | 0.1-0.25 | >0.25 |
| TTFB | ≤800ms | 800-1800ms | >1800ms |
| FCP | ≤1.8s | 1.8-3s | >3s |
SESSION="--session-id perf-audit"
# 1. Navigate to page
browser-devtools-cli $SESSION navigation go-to --url "https://example.com"
# 2. Wait for page to settle
browser-devtools-cli $SESSION sync wait-for-network-idle
# 3. Get Web Vitals
browser-devtools-cli $SESSION --json o11y get-web-vitals --wait-ms 2000
# 4. Analyze network requests
browser-devtools-cli $SESSION --json o11y get-http-requests
# 5. Check for console errors
browser-devtools-cli $SESSION --json o11y get-console-messages --type warning
# 6. Take screenshot for reference
browser-devtools-cli $SESSION content take-screenshot --name "performance-audit"
# 7. Cleanup
browser-devtools-cli session delete perf-audit
# Filter by type (one at a time: document, stylesheet, image, script, xhr, fetch, etc.)
browser-devtools-cli --json o11y get-http-requests --resource-type script
browser-devtools-cli --json o11y get-http-requests --resource-type stylesheet
browser-devtools-cli --json o11y get-http-requests --resource-type image
browser-devtools-cli --json o11y get-http-requests
# Look for requests with high timing values
When TTFB or API latency suggests backend bottlenecks, inspect the Node.js process:
# Connect to API/server process
node-devtools-cli --session-id perf debug connect --pid 12345
# Tracepoint on slow handler to capture call context
node-devtools-cli --session-id perf debug put-tracepoint \
--url-pattern "routes/heavy.ts" \
--line-number 30