Core Web Vitals
theopenco/llmgateway
Diagnose and improve Largest Contentful Paint, Interaction to Next Paint, and Cumulative Layout Shift in this repository's Next.js App Router frontends.
A skill your agent uses when auditing slow page loads, heavy assets, or rendering delays related to Optimize largest contentful paint.
Install Largest Contentful Paint
$ npx skills add thedaviddias/Front-End-Checklist --skill largest-contentful-paint -a claude-codeProject install by default; add -g for ~/.claude/skills/.
$ gh skill install thedaviddias/Front-End-Checklist largest-contentful-paint --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/thedaviddias/Front-End-Checklist.git skills-src && mkdir -p .claude/skills && cp -r skills-src/skills/largest-contentful-paint .claude/skills/largest-contentful-paint && 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 "largest-contentful-paint" agent skill from https://github.com/thedaviddias/Front-End-Checklist/tree/main/skills/largest-contentful-paint into .claude/skills/largest-contentful-paint/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "largest-contentful-paint", 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/thedaviddias/Front-End-Checklist/tree/main/skills/largest-contentful-paintType 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 thedaviddias/Front-End-Checklist --skill largest-contentful-paint -a codexProject install goes to .agents/skills/; add -g for ~/.codex/skills/.
$ gh skill install thedaviddias/Front-End-Checklist largest-contentful-paint --agent codexProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/thedaviddias/Front-End-Checklist.git skills-src && mkdir -p .agents/skills && cp -r skills-src/skills/largest-contentful-paint .agents/skills/largest-contentful-paint && rm -rf skills-srcUse ~/.agents/skills/ instead of .agents/skills for a personal install.
Codex skills documentation · loads skills from .agents/skills/
Install the "largest-contentful-paint" agent skill from https://github.com/thedaviddias/Front-End-Checklist/tree/main/skills/largest-contentful-paint into .agents/skills/largest-contentful-paint/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "largest-contentful-paint", 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 thedaviddias/Front-End-Checklist --skill largest-contentful-paint -a cursorProject install goes to .agents/skills/; add -g for ~/.cursor/skills/.
$ gh skill install thedaviddias/Front-End-Checklist largest-contentful-paint --agent cursorProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/thedaviddias/Front-End-Checklist.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/skills/largest-contentful-paint .cursor/skills/largest-contentful-paint && 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 "largest-contentful-paint" agent skill from https://github.com/thedaviddias/Front-End-Checklist/tree/main/skills/largest-contentful-paint into .cursor/skills/largest-contentful-paint/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "largest-contentful-paint", 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/thedaviddias/Front-End-Checklist.git --path skills/largest-contentful-paint--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 thedaviddias/Front-End-Checklist --skill largest-contentful-paint -a gemini-cliProject install goes to .agents/skills/; add -g for ~/.gemini/skills/.
$ gh skill install thedaviddias/Front-End-Checklist largest-contentful-paint --agent gemini-cliProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/thedaviddias/Front-End-Checklist.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/skills/largest-contentful-paint .gemini/skills/largest-contentful-paint && 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 "largest-contentful-paint" agent skill from https://github.com/thedaviddias/Front-End-Checklist/tree/main/skills/largest-contentful-paint into .gemini/skills/largest-contentful-paint/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "largest-contentful-paint", 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 thedaviddias/Front-End-Checklist largest-contentful-paintInstalls 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 thedaviddias/Front-End-Checklist --skill largest-contentful-paint -a github-copilotProject install goes to .agents/skills/; add -g for ~/.copilot/skills/.
$ git clone --depth 1 https://github.com/thedaviddias/Front-End-Checklist.git skills-src && mkdir -p .github/skills && cp -r skills-src/skills/largest-contentful-paint .github/skills/largest-contentful-paint && 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 "largest-contentful-paint" agent skill from https://github.com/thedaviddias/Front-End-Checklist/tree/main/skills/largest-contentful-paint into .github/skills/largest-contentful-paint/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "largest-contentful-paint", 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 thedaviddias/Front-End-Checklist --skill largest-contentful-paint -a opencodeOpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.
$ gh skill install thedaviddias/Front-End-Checklist largest-contentful-paint --agent opencodeProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/thedaviddias/Front-End-Checklist.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/skills/largest-contentful-paint .opencode/skills/largest-contentful-paint && 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 "largest-contentful-paint" agent skill from https://github.com/thedaviddias/Front-End-Checklist/tree/main/skills/largest-contentful-paint into .opencode/skills/largest-contentful-paint/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "largest-contentful-paint", 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
largest-contentful-paint- GitHub stars
- 74k
- Token cost
- ~441 tokens
- SKILL.md length
- 166 words
- Files
- 2 (incl. references)
- Skills in repo
- 390
- Repo updated
- First seen
- Licence
- MIT
At a glance
A skill your agent uses when auditing slow page loads, heavy assets, or rendering delays related to Optimize largest contentful paint.
- Auditing slow page loads
- SKILL.md covers Quick Reference, Check, Fix and Explain, plus 1 more section
- Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md
- Rendering delays related to Optimize largest contentful paint
What it does
Largest Contentful Paint is an agent skill from thedaviddias/Front-End-Checklist. Use when auditing slow page loads, heavy assets, or rendering delays related to Optimize largest contentful paint. Verify the actual bottleneck in DevTools, Lighthouse, or field data before recommending changes.
Its SKILL.md is about 440 tokens, which your agent loads only when the skill is triggered. The skill folder holds 2 other files, including reference files (for example `references/rule.md`).
It sits in Frontend & Design, covering Web performance. It works with Contentful. The repository describes itself as: 🗂 The essential checklist for modern web development, for humans and AI agents. The licence is MIT.
When your agent uses it
- Auditing slow page loads
- Rendering delays related to Optimize largest contentful paint
Example prompts
- “/largest-contentful-paint”
What it can do on your machine
Read from SKILL.md and the folder at commit e8d14d0. 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
No scripts in the folder and no shell commands in SKILL.md.
From the folder's file list and the shell code blocks in SKILL.md.
Network
Links to these hosts (documentation or services it may open):
frontendchecklist.io
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
Largest Contentful Paint loads about 441 tokens when it runs, and up to ~1.5k if it reads all its reference files. Until then it costs about 59 tokens; SKILL.md has 166 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
The full file from thedaviddias/Front-End-Checklist at commit e8d14d0, republished under its MIT licence (© thedaviddias). 166 words, ~441 tokens.
Download SKILL.mdSave it as
.claude/skills/largest-contentful-paint/SKILL.md (or your agent's skills folder). This skill also uses 1 other file; get the full folder from GitHub.- name
- largest-contentful-paint
- description
- Use when auditing slow page loads, heavy assets, or rendering delays related to Optimize largest contentful paint. Verify the actual bottleneck in DevTools, Lighthouse, or field data before recommending changes.
- metadata.category
- performance
- metadata.priority
- critical
- metadata.difficulty
- intermediate
- metadata.estimatedTime
- 25
- metadata.source
- frontendchecklist.io
- metadata.url
- https://frontendchecklist.io/rules/performance/largest-contentful-paint
Optimize largest contentful paint
LCP is the most important Core Web Vital for perceived load speed—it measures when the main content becomes visible, directly impacting user perception and SEO rankings.
Quick Reference
- LCP measures when the largest element renders—target under 2.5s
- Use preload for hero images and critical resources
- Optimize image formats and use responsive sizes
- Reduce server response time (TTFB)
Check
Measure LCP using Lighthouse or PageSpeed Insights. Verify the largest visible element renders within 2.5 seconds.
Fix
Optimize LCP by preloading critical resources, optimizing images, using CDN, and reducing server response time.
Explain
Explain how LCP measures perceived load speed by tracking when the largest visible content element becomes visible.
Code Review
Review the routes, assets, and loading behavior that affect Optimize largest contentful paint. Flag exact files, requests, or rendering steps that add unnecessary network, CPU, or layout cost, and describe the measurement method used to confirm the issue.
For full implementation details, code examples, and framework-specific guidance,
see references/rule.md.
Rule page: https://frontendchecklist.io/rules/performance/largest-contentful-paint
© thedaviddias, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file
Files
SKILL.md and 1 other file (references) in skills/largest-contentful-paint of thedaviddias/Front-End-Checklist.
- SKILL.md
- references/rule.md
Open the folder on GitHubat commit e8d14d0
Compare with similar skills
Largest Contentful Paint 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 |
|---|---|---|---|---|---|---|
| Largest Contentful Paint this skillthedaviddias/Front-End-Checklist | 74k | — | ~441 | Automated safety check: Pass | MIT | |
| Core Web Vitalstheopenco/llmgateway | 1.7k | — | ~955 | Automated safety check: Pass | Custom licence | |
| Performance ProfilerEliasOulkadi/shokunin | 114 | — | ~2.7k | Automated safety check: Notes | MIT | |
| Algo SEO Technicalasgard-ai-platform/skills | 242 | — | ~1k | Automated safety check: Pass | MIT | |
| Core Web Vitalskostja94/marketing-skills | 1k | — | ~1.2k | Automated safety check: Pass | MIT | |
| React Doctormakeplane/plane | 61k | 12 repos | ~657 | Automated safety check: Pass | AGPL-3.0 |
Similar skills
Performance Profiler
EliasOulkadi/shokunin
Performance profiling and optimization for web apps — Core Web Vitals (LCP, INP, CLS), Lighthouse audits, bundle analysis, backend profiling (CPU, memory, DB queries), N+1 detection, caching…
Algo SEO Technical
asgard-ai-platform/skills
Optimize Core Web Vitals (LCP, INP, CLS) for better search rankings and user experience.
Core Web Vitals
kostja94/marketing-skills
When the user wants to optimize Core Web Vitals, fix LCP, INP, or CLS issues.
React Doctor
makeplane/plane
Scans React code for lint, accessibility, bundle size and architecture issues, reports a health score and checks that changes do not lower it.
Fixing Motion Performance
ibelick/ui-skills
Audits and fixes web animation performance: layout thrashing, work that belongs on the compositor, scroll-linked motion and costly blur effects.
More from thedaviddias/Front-End-Checklist
All 390 skills in this repoContent Dates Audit
thedaviddias/Front-End-Checklist
Audits article and blog pages for visible publish dates, Article JSON-LD with datePublished and dateModified, and Open Graph time tags, then fixes what is missing.
FAQPage Schema Markup
thedaviddias/Front-End-Checklist
Adds, checks and fixes FAQPage JSON-LD on pages with visible question-and-answer sections so it matches what readers see and can qualify for rich results.
Favicon Audit and Setup
thedaviddias/Front-End-Checklist
Checks that a site's favicon is linked, reachable and large enough for Google search results, and sets up ICO, SVG and Apple touch icon files when they are missing.
Content Freshness Signals
thedaviddias/Front-End-Checklist
Audits article pages for freshness signals, covering the Last-Modified header, Article JSON-LD dateModified and a visible last-updated date, and fixes mismatches.
Geo Meta Tags Audit
thedaviddias/Front-End-Checklist
Audits and fixes geo.region, geo.placename and geo.position meta tags on regional pages, noting where they help (Bing) and where they do not (Google).
Improve a Front-End Checklist Rule
thedaviddias/Front-End-Checklist
Scores and rewrites a Front-End Checklist rule MDX file against a scored quality rubric, replacing generic stub prompts with specific, actionable ones.
Related
Works with
Categories
Questions about Largest Contentful Paint
What does Largest Contentful Paint do?
A skill your agent uses when auditing slow page loads, heavy assets, or rendering delays related to Optimize largest contentful paint. Largest Contentful Paint is an agent skill from thedaviddias/Front-End-Checklist. Use when auditing slow page loads, heavy assets, or rendering delays related to Optimize largest contentful paint.
When should I use Largest Contentful Paint?
Largest Contentful Paint fits situations like: auditing slow page loads; rendering delays related to Optimize largest contentful paint.
How do I install Largest Contentful Paint in Claude Code?
Run `npx skills add thedaviddias/Front-End-Checklist --skill largest-contentful-paint -a claude-code`. Or copy the skill folder (skills/largest-contentful-paint in thedaviddias/Front-End-Checklist) into .claude/skills/largest-contentful-paint in your project. Claude Code loads it when a task matches its description.
How do I install Largest Contentful Paint in Codex?
Run `npx skills add thedaviddias/Front-End-Checklist --skill largest-contentful-paint -a codex`. Or copy the skill folder (skills/largest-contentful-paint in thedaviddias/Front-End-Checklist) into .agents/skills/largest-contentful-paint in your project. Codex loads it when a task matches its description.
Can I use Largest Contentful Paint 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 thedaviddias/Front-End-Checklist --skill largest-contentful-paint -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/largest-contentful-paint, .gemini/skills/largest-contentful-paint, .github/skills/largest-contentful-paint and .opencode/skills/largest-contentful-paint in your project.
What does Largest Contentful Paint need to run?
SKILL.md names no scripts, command-line tools or credentials: Largest Contentful Paint is instructions for the agent only.
Does Largest Contentful Paint access the network?
SKILL.md names 1 domain. As links in the text: frontendchecklist.io. This is read from the text; nothing was executed.
Is Largest Contentful Paint 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 Largest Contentful Paint use?
Largest Contentful Paint is published under the MIT licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.
How many tokens does Largest Contentful Paint use?
About 441 tokens (SKILL.md is roughly 1.8k 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 1.1k tokens, read only when the agent opens those files.
What are the alternatives to Largest Contentful Paint?
Skills that share tags, products or a category with Largest Contentful Paint: Core Web Vitals (theopenco/llmgateway, 1.7k stars), Performance Profiler (EliasOulkadi/shokunin, 114 stars), Algo SEO Technical (asgard-ai-platform/skills, 242 stars) and Core Web Vitals (kostja94/marketing-skills, 1k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.
Who maintains Largest Contentful Paint?
thedaviddias (a GitHub user) maintains it in thedaviddias/Front-End-Checklist, which has 74,421 GitHub stars. The repository holds 390 skills in this directory. The repository was last updated on October 6, 2026.
Source: thedaviddias/Front-End-Checklist on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.