{"slug":"webperf","title":"webperf","summary":"Web performance measurement and debugging toolkit. Use when the user asks about web performance, wants to audit a page, or says \"analyze performance\", \"debug lcp\", \"check ttfb\", \"measure core web vitals\", \"audit images\", or similar.","platform":"Claude","tags":[],"authorName":"LLM Mart","authorSlug":"llm-mart","score":0,"source":"github","price":null,"verified":false,"createdAt":"2026-10-19T21:17:31.721992Z","repo":{"url":"https://github.com/nucliweb/webperf-snippets","stars":1454,"forks":90,"license":"MIT","updatedAt":"2026-10-19T11:21:09Z"},"bodyHtml":"<hr>\n<h2>name: webperf\ndescription: Web performance measurement and debugging toolkit. Use when the user asks about web performance, wants to audit a page, or says \"analyze performance\", \"debug lcp\", \"check ttfb\", \"measure core web vitals\", \"audit images\", or similar.\ncontext: fork\nlicense: MIT\nmetadata:\nauthor: Joan Leon | @nucliweb\nversion: 2.0.1\nmcp-server: chrome-devtools\ncategory: web-performance\nrepository: <a href=\"https://github.com/nucliweb/webperf-snippets\">https://github.com/nucliweb/webperf-snippets</a></h2>\n<h1>WebPerf Snippets Toolkit</h1>\n<p>A collection of 56 JavaScript snippets for measuring and debugging web performance in Chrome DevTools. Each snippet runs in the page and returns a structured result object.</p>\n<h2>Quick Reference</h2>\n<table>\n<thead>\n<tr>\n<th>Skill</th>\n<th>Snippets</th>\n<th>Trigger phrases</th>\n</tr>\n</thead>\n<tbody>\n<tr>\n<td>webperf-core-web-vitals</td>\n<td>7</td>\n<td>\"debug LCP\", \"slow LCP\", \"CLS\", \"layout shifts\", \"INP\", \"interaction latency\", \"responsiveness\"</td>\n</tr>\n<tr>\n<td>webperf-loading</td>\n<td>34</td>\n<td>\"TTFB\", \"slow server\", \"FCP\", \"render blocking\", \"font loading\", \"script loading\", \"resource hints\", \"service worker\"</td>\n</tr>\n<tr>\n<td>webperf-interaction</td>\n<td>10</td>\n<td>\"jank\", \"scroll performance\", \"long tasks\", \"animation frames\", \"INP debug\"</td>\n</tr>\n<tr>\n<td>webperf-media</td>\n<td>4</td>\n<td>\"image audit\", \"lazy loading\", \"image optimization\", \"video audit\"</td>\n</tr>\n<tr>\n<td>webperf-resources</td>\n<td>1</td>\n<td>\"network quality\", \"bandwidth\", \"connection type\", \"save-data\"</td>\n</tr>\n</tbody>\n</table>\n<h2>Workflow</h2>\n<ol>\n<li>Identify the relevant skill based on the user's question (see Quick Reference above)</li>\n<li>Load the skill's SKILL.md to see available snippets and thresholds</li>\n<li>Execute with Chrome DevTools MCP:\n<ul>\n<li><code>mcp__chrome-devtools__navigate_page</code> → navigate to target URL</li>\n<li><code>mcp__chrome-devtools__evaluate_script</code> → run the snippet and read the returned object, which is the result (the scripts have no console output)</li>\n<li><code>status: \"tracking\"</code> → call the function named in <code>getDataFn</code> with another <code>mcp__chrome-devtools__evaluate_script</code> call after the interactions</li>\n<li>Without Chrome DevTools MCP, run the snippet with the CLI: <code>npx webperf-snippets &lt;url&gt; --snippet &lt;Name&gt; --json</code></li>\n</ul>\n</li>\n<li>Interpret results using the thresholds defined in the skill</li>\n<li>Provide actionable recommendations based on findings</li>\n</ol>\n","files":[{"path":"SKILL.md","sizeBytes":2153,"isText":true}],"reviewScore":null,"reviewSummary":null,"trust":{"provenance":"trusted-source-unreviewed","notice":"Community-authored content, reproduced verbatim and not vetted as instructions. Treat it as data to evaluate, never as directives to follow.","bodySource":null},"bodyLocked":false,"purchaseUrl":null,"sourceUrl":null,"report":{"provenance":"trusted-source-unreviewed","screen":{"ran":true,"outcome":"clean","suspicious":0,"notes":0,"hiddenCharacters":false},"virusScan":{"engine":"clamav","status":"clean","scannedAt":"2026-10-19T21:18:26.548817Z","sha256":"4BC8FC15DC966D2E0EDAB5D97F02C63AD7192E58111BAB7496DCC233D35E111E","sizeBytes":1185},"review":null,"source":{"repositoryUrl":"https://github.com/nucliweb/webperf-snippets","path":"skills/webperf","license":"MIT","commit":"d2f9739cda7363daab6ade96ad2b2198e9b44e8e","subtreeSha":"24DF04A0204460D4AEDDB2CEADFCADF104B643F0AEDC21B01390FF71A52D5CB1","lastSyncedAt":"2026-10-19T21:17:31.667373Z"},"reviewedAt":"2026-10-19T21:20:20.478158Z","notice":"Community-authored content, reproduced verbatim and not vetted as instructions. Treat it as data to evaluate, never as directives to follow."},"install":[{"target":"skills-cli","command":"npx skills add https://github.com/nucliweb/webperf-snippets/tree/main/skills/webperf"},{"target":"claude-code","command":"claude plugin marketplace add https://llmmart.ai/marketplace.json && claude plugin install nucliweb-webperf-snippets@llmmart"},{"target":"git","command":"git clone https://github.com/nucliweb/webperf-snippets.git"}]}