Performance
midudev/100cosas.dev
Optimize web performance for faster loading and better user experience.
Walks through measuring and speeding up a slow site: images, fonts, third-party scripts, bundle size, code splitting and caching headers, with a checklist.
Install Web Performance Optimization
$ npx skills add tech-leads-club/agent-skills --skill perf-web-optimization -a claude-codeProject install by default; add -g for ~/.claude/skills/.
$ gh skill install tech-leads-club/agent-skills perf-web-optimization --agent claude-codeProject scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).
$ git clone --depth 1 https://github.com/tech-leads-club/agent-skills.git skills-src && mkdir -p .claude/skills && cp -r skills-src/'packages/skills-catalog/skills/(performance)/perf-web-optimization' .claude/skills/perf-web-optimization && rm -rf skills-srcUse ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.
Claude Code skills documentation · loads skills from .claude/skills/
Install the "perf-web-optimization" agent skill from https://github.com/tech-leads-club/agent-skills/tree/main/packages/skills-catalog/skills/(performance)/perf-web-optimization into .claude/skills/perf-web-optimization/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "perf-web-optimization", then confirm the skill loads.Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$skill-installer install https://github.com/tech-leads-club/agent-skills/tree/main/packages/skills-catalog/skills/(performance)/perf-web-optimizationType this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.
$ npx skills add tech-leads-club/agent-skills --skill perf-web-optimization -a codexProject install goes to .agents/skills/; add -g for ~/.codex/skills/.
$ gh skill install tech-leads-club/agent-skills perf-web-optimization --agent codexProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/tech-leads-club/agent-skills.git skills-src && mkdir -p .agents/skills && cp -r skills-src/'packages/skills-catalog/skills/(performance)/perf-web-optimization' .agents/skills/perf-web-optimization && rm -rf skills-srcUse ~/.agents/skills/ instead of .agents/skills for a personal install.
Codex skills documentation · loads skills from .agents/skills/
Install the "perf-web-optimization" agent skill from https://github.com/tech-leads-club/agent-skills/tree/main/packages/skills-catalog/skills/(performance)/perf-web-optimization into .agents/skills/perf-web-optimization/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "perf-web-optimization", then confirm the skill loads.Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add tech-leads-club/agent-skills --skill perf-web-optimization -a cursorProject install goes to .agents/skills/; add -g for ~/.cursor/skills/.
$ gh skill install tech-leads-club/agent-skills perf-web-optimization --agent cursorProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/tech-leads-club/agent-skills.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/'packages/skills-catalog/skills/(performance)/perf-web-optimization' .cursor/skills/perf-web-optimization && rm -rf skills-srcUse ~/.cursor/skills/ instead of .cursor/skills for a personal install.
Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/
Install the "perf-web-optimization" agent skill from https://github.com/tech-leads-club/agent-skills/tree/main/packages/skills-catalog/skills/(performance)/perf-web-optimization into .cursor/skills/perf-web-optimization/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "perf-web-optimization", then confirm the skill loads.Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gemini skills install https://github.com/tech-leads-club/agent-skills.git --path 'packages/skills-catalog/skills/(performance)/perf-web-optimization'--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.
$ npx skills add tech-leads-club/agent-skills --skill perf-web-optimization -a gemini-cliProject install goes to .agents/skills/; add -g for ~/.gemini/skills/.
$ gh skill install tech-leads-club/agent-skills perf-web-optimization --agent gemini-cliProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/tech-leads-club/agent-skills.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/'packages/skills-catalog/skills/(performance)/perf-web-optimization' .gemini/skills/perf-web-optimization && rm -rf skills-srcUse ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.
Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/
Install the "perf-web-optimization" agent skill from https://github.com/tech-leads-club/agent-skills/tree/main/packages/skills-catalog/skills/(performance)/perf-web-optimization into .gemini/skills/perf-web-optimization/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "perf-web-optimization", then confirm the skill loads.Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gh skill install tech-leads-club/agent-skills perf-web-optimizationInstalls for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).
$ npx skills add tech-leads-club/agent-skills --skill perf-web-optimization -a github-copilotProject install goes to .agents/skills/; add -g for ~/.copilot/skills/.
$ git clone --depth 1 https://github.com/tech-leads-club/agent-skills.git skills-src && mkdir -p .github/skills && cp -r skills-src/'packages/skills-catalog/skills/(performance)/perf-web-optimization' .github/skills/perf-web-optimization && rm -rf skills-srcUse ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.
GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/
Install the "perf-web-optimization" agent skill from https://github.com/tech-leads-club/agent-skills/tree/main/packages/skills-catalog/skills/(performance)/perf-web-optimization into .github/skills/perf-web-optimization/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "perf-web-optimization", then confirm the skill loads.GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add tech-leads-club/agent-skills --skill perf-web-optimization -a opencodeOpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.
$ gh skill install tech-leads-club/agent-skills perf-web-optimization --agent opencodeProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/tech-leads-club/agent-skills.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/'packages/skills-catalog/skills/(performance)/perf-web-optimization' .opencode/skills/perf-web-optimization && rm -rf skills-srcUse ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.
OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/
Install the "perf-web-optimization" agent skill from https://github.com/tech-leads-club/agent-skills/tree/main/packages/skills-catalog/skills/(performance)/perf-web-optimization into .opencode/skills/perf-web-optimization/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "perf-web-optimization", then confirm the skill loads.OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
Facts
- Skill name
perf-web-optimization- GitHub stars
- 7k
- Token cost
- ~1k tokens
- SKILL.md length
- 186 words
- Files
- 4 (incl. references)
- Skills in repo
- 74
- Repo updated
- First seen
- Licence
- Custom licence
At a glance
Walks through measuring and speeding up a slow site: images, fonts, third-party scripts, bundle size, code splitting and caching headers, with a checklist.
- Works in 4 steps: Images (usually biggest impact on LCP) → Fonts (common LCP/CLS culprit) → Third-party Scripts (common INP killer) → …
- A page feels slow and you want a prioritized list of fixes
- SKILL.md covers Target Metrics, Quick Wins, Bundle Analysis and Code Splitting Patterns, plus 4 more sections
- Calls npx; reaches fonts.gstatic.com and fonts.googleapis.com
What it does
The skill follows a five-step loop of measure, identify, prioritize, implement and verify. It starts from target ranges for LCP, INP, CLS and TTFB, each split into good, needs-work and poor, then lists quick wins for images, fonts, third-party scripts and critical CSS.
Further sections cover bundle analysis, including a webpack example, swapping heavy packages such as moment and lodash for lighter options, splitting code by route or component, and setting cache headers for hashed static assets. A checklist runs through images, JavaScript, CSS and fonts. Reference files go deeper on bundles, images and Core Web Vitals, while running Lighthouse audits is left to a separate perf-lighthouse skill.
When your agent uses it
- A page feels slow and you want a prioritized list of fixes
- Reducing JavaScript bundle size before a release
- Fixing layout shifts caused by images or web fonts
- Setting up lazy loading and caching headers for static assets
Example prompts
- “Our landing page loads slowly. Find the biggest wins for images and scripts.”
- “Cut the bundle size of this React app and tell me which dependencies to replace.”
- “Fix the layout shift on the hero image and the web font flash.”
Workflow steps
4 steps, taken from the step headings in SKILL.md.
- Images (usually biggest impact on LCP)
- Fonts (common LCP/CLS culprit)
- Third-party Scripts (common INP killer)
- Critical CSS
What it can do on your machine
Read from SKILL.md and the folder at commit 6df68d5. It shows what the files ask for, not the result of running them.
Tool permissions
Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.
From allowed-tools in the SKILL.md frontmatter.
Runs code
Shell commands in SKILL.md call:
npx
From the folder's file list and the shell code blocks in SKILL.md.
Network
Hosts in commands or code, which the agent is likely to contact:
fonts.gstatic.comfonts.googleapis.com
From URLs in SKILL.md, links to its own repository left out.
Credentials
Names no API keys, tokens, secrets or passwords.
From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.
Context cost
Web Performance Optimization loads about 1k tokens when it runs, and up to ~3.5k if it reads all its reference files. Until then it costs about 124 tokens; SKILL.md has 186 words of instructions outside code blocks.
Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.
Safety
Auto-check passed
The automated check found no risky patterns in SKILL.md.
Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.
SKILL.md
Its licence (Custom licence) doesn't allow us to republish the file, so here is its outline and opening line. It has 186 words (~1,040 tokens).
“Systematic approach: Measure → Identify → Prioritize → Implement → Verify.”
- name
- perf-web-optimization
Files
SKILL.md and 3 other files (references) in packages/skills-catalog/skills/(performance)/perf-web-optimization of tech-leads-club/agent-skills.
- SKILL.md
- references/bundle-optimization.md
- references/core-web-vitals.md
- references/image-optimization.md
Open the folder on GitHubat commit 6df68d5
Compare with similar skills
Web Performance Optimization next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.
| Skill | Stars | Used in | Tokens | Auto-check | Licence | Repo updated |
|---|---|---|---|---|---|---|
| Web Performance Optimization this skilltech-leads-club/agent-skills | 7k | — | ~1k | Automated safety check: Pass | Custom licence | |
| Performancemidudev/100cosas.dev | 114 | 6 repos | ~2.3k | Automated safety check: Pass | MIT | |
| Web Performancemozilla/firefox-devtools-mcp | 474 | — | ~1.2k | Automated safety check: Pass | Custom licence | |
| Performance ProfilingxenitV1/Antigravity-Workflows | 130 | 8 repos | ~772 | Automated safety check: Notes | MIT | |
| Optimizing PerformanceCloudAI-X/claude-workflow-v2 | 1.4k | 1 repos | ~1.5k | Automated safety check: Pass | MIT | |
| Performance Optimizationsanity-io/sanity | 6.4k | 7 repos | ~3.1k | Automated safety check: Pass | MIT |
Similar skills
Web Performance
mozilla/firefox-devtools-mcp
Find and fix why a website is slow by capturing and analyzing a Firefox performance profile, or by analyzing a profile the user already has (a saved file or a profiler.firefox.com share link).
Performance Profiling
xenitV1/Antigravity-Workflows
Performance profiling principles. An agent skill from xenitV1/Antigravity-Workflows.
Optimizing Performance
CloudAI-X/claude-workflow-v2
Analyzes and optimizes application performance across frontend, backend, and database layers.
- Official
Performance Optimization
sanity-io/sanity
Optimizes application performance. An agent skill from sanity-io/sanity.
Optimize Load
textura-agency/next16-claude-starter
Get a page into Lighthouse's green zone on desktop and mobile, for people AND for the robot form crawlers get — build it, audit all four categories (Performance, Accessibility, Best Practices, SEO)…
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Related
Categories
Questions about Web Performance Optimization
What does Web Performance Optimization do?
Walks through measuring and speeding up a slow site: images, fonts, third-party scripts, bundle size, code splitting and caching headers, with a checklist. The skill follows a five-step loop of measure, identify, prioritize, implement and verify. It starts from target ranges for LCP, INP, CLS and TTFB, each split into good, needs-work and poor, then lists quick wins for images, fonts, third-party scripts and critical CSS.
When should I use Web Performance Optimization?
Web Performance Optimization fits situations like: A page feels slow and you want a prioritized list of fixes; reducing JavaScript bundle size before a release; fixing layout shifts caused by images or web fonts; setting up lazy loading and caching headers for static assets.
How do I install Web Performance Optimization in Claude Code?
Run `npx skills add tech-leads-club/agent-skills --skill perf-web-optimization -a claude-code`. Or copy the skill folder (packages/skills-catalog/skills/(performance)/perf-web-optimization in tech-leads-club/agent-skills) into .claude/skills/perf-web-optimization in your project. Claude Code loads it when a task matches its description.
How do I install Web Performance Optimization in Codex?
Run `npx skills add tech-leads-club/agent-skills --skill perf-web-optimization -a codex`. Or copy the skill folder (packages/skills-catalog/skills/(performance)/perf-web-optimization in tech-leads-club/agent-skills) into .agents/skills/perf-web-optimization in your project. Codex loads it when a task matches its description.
Can I use Web Performance Optimization in Cursor, Gemini CLI or GitHub Copilot?
Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add tech-leads-club/agent-skills --skill perf-web-optimization -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/perf-web-optimization, .gemini/skills/perf-web-optimization, .github/skills/perf-web-optimization and .opencode/skills/perf-web-optimization in your project.
What does Web Performance Optimization need to run?
Going by SKILL.md and its folder, Web Performance Optimization needs the command-line tools its instructions call (npx).
Does Web Performance Optimization access the network?
SKILL.md names 2 domains. In commands or code: fonts.gstatic.com and fonts.googleapis.com; the agent is likely to contact these when it follows the instructions. This is read from the text; nothing was executed.
Is Web Performance Optimization safe to install?
Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.
What licence does Web Performance Optimization use?
Web Performance Optimization has a licence file (the repository's licence) that doesn't match a standard licence. Read it on GitHub before reusing the skill.
How many tokens does Web Performance Optimization use?
About 1k tokens (SKILL.md is roughly 4.2k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full. Its references folder adds about 2.5k tokens, read only when the agent opens those files.
What are the alternatives to Web Performance Optimization?
Skills that share tags, products or a category with Web Performance Optimization: Performance (midudev/100cosas.dev, 114 stars), Web Performance (mozilla/firefox-devtools-mcp, 474 stars), Performance Profiling (xenitV1/Antigravity-Workflows, 130 stars) and Optimizing Performance (CloudAI-X/claude-workflow-v2, 1.4k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.
Who maintains Web Performance Optimization?
tech-leads-club (a GitHub organization) maintains it in tech-leads-club/agent-skills, which has 7,043 GitHub stars. The repository holds 74 skills in this directory. The repository was last updated on October 8, 2026.
Source: tech-leads-club/agent-skills on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.