Front-End Checklist is a collection of front-end web development rules organized as a practical review and quality workflow for people and AI agents. Developers use it to audit projects and pull requests, check implementation details, and find guidance for remediation and verification. The catalogue entries provide skills, instructions, MCP tools, and a plugin for using the checklist in agent workflows.
Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add thedaviddias/Front-End-Checklist --skill broken-imagesgit clone --depth 1 https://github.com/thedaviddias/Front-End-ChecklistWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/thedaviddias/front-end-checklist/broken-images)<a href="https://agentmods.dev/skills/thedaviddias/front-end-checklist/broken-images"><img src="https://agentmods.dev/badge/skills/thedaviddias/front-end-checklist/broken-images/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/thedaviddias/front-end-checklist/broken-images"><img src="https://agentmods.dev/badge/skills/thedaviddias/front-end-checklist/broken-images.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00039 | $0.00613 |
| Opus 5.5 | $0.00016 | $0.00245 |
| Sonnet 5.5 | $0.00008 | $0.00123 |
| Haiku 4.5 | $0.00004 | $0.00061 |
Grade A, and why
broken-images scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 23d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 46 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Fix broken images
A broken image shows an ugly placeholder icon, breaks visual layouts, and communicates that the site is poorly maintained. If the broken image is the Largest Contentful Paint element, it also harms LCP scores. On e-commerce sites, a missing product image can directly reduce purchase intent.
Quick Reference
- Broken images show an icon and console error—validate all
<img src>paths at build time - Use
onerrorhandlers to swap broken<img>elements to fallback images - Set
this.onerror=nullinside the handler to prevent infinite error loops - Test with DevTools Network tab blocked requests to verify fallback behaviour
Check
Scan all src attributes and CSS background-image URLs in this codebase. Identify: 1) Any relative or absolute paths that point to files not present in the project. 2) Any elements without an onerror handler or fallback mechanism. 3) Hardcoded external image URLs that may become unavailable. 4) Dynamic image paths constructed from user data without existence checks. Report each broken or potentially broken image with its file path and line number.
Fix
For each broken image: 1) Correct the file path if the image exists but the path is wrong. 2) Add the missing image asset if it was omitted. 3) For images that may fail at runtime, add an onerror handler: onerror="this.src='/images/fallback.png'; this.onerror=null;". 4) For React/Vue components, implement an onError callback that swaps the src to a placeholder. 5) For external images, consider downloading and self-hosting or using a CDN with fallback. Always set this.onerror=null to prevent infinite error loops.
Explain
Explain why broken images degrade user experience and how browsers handle them. A 404 response for an image shows the browser's broken-image icon, causes a console error, and—if the image is the LCP element—delays Core Web Vitals metrics. Search engines cannot index missing images, affecting image SEO. Monitoring image errors proactively prevents broken experiences from reaching users.
What ships with it
1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 23d ago Changed 20ce84468063
- 1mo ago First seen · 46 lines · 39 tokens per session scan A 970d5deb899d
broken-images is a skill published in the GitHub repository thedaviddias/Front-End-Checklist (74,577 stars, last pushed 21d ago), licensed MIT. It adds 39 tokens to every session and 613 once invoked, about $0.0002 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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