4XX Pages in Sitemap

SkillWeb & browsing

sitemap-4xx is a skill that checks a website's XML sitemap for broken links. It works with any site that has a dynamically generated or manually maintained XML sitemap, letting your agent find dead URLs and crawl errors. It is useful when investigating crawl errors or after a site migration that removed pages.

Use 4XX Pages in Sitemap in Claude, ChatGPT or Ahel Desktop

Free. Sign in, add 4XX Pages in Sitemap and connect your AI. About a minute.

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Then ask your AI: use the 4XX Pages in Sitemap skill

Details

Instructions available. Your AI can read the instructions. Execution depends on the setup they require.

Have an AI agent that can load skills.

4XX Pages in SitemapStart free

What your AI can do with it

  • Check a website's XML sitemap for broken links
  • Find dead URLs listed in a sitemap
  • Surface crawl errors for a site
  • Audit pages after a site migration that removed pages
  • Work with dynamically generated or manually maintained XML sitemaps

Getting started

  1. Have an AI agent that can load skills.
  2. Add the sitemap-4xx skill to the agent.
  3. Provide the URL of the XML sitemap you want checked.
  4. Ask the agent to check the sitemap for broken links or crawl errors.

What this skill tells your AI

The instructions your AI receives, as published by thedaviddias/front-end-checklist in skills/sitemap-4xx/SKILL.md and read by ahel’s review.

Including 4XX URLs in a sitemap signals poor site maintenance to Google, wastes crawl budget on non-existent pages, and generates errors in Search Console that can mask real indexing issues.

Quick Reference

  • Sitemaps should only contain URLs that return HTTP 200 and are indexable
  • 4XX URLs in a sitemap waste crawl budget and cause Search Console errors
  • Remove 404 pages from the sitemap or set up proper 301 redirects before adding them
  • Monitor the sitemap regularly — deleted content must be removed from sitemaps promptly

Check

Fetch all URLs listed in the sitemap and record their HTTP status codes. Flag any URL returning 4XX (404 Not Found, 410 Gone, 403 Forbidden). Cross-reference against Google Search Console → Coverage for corroborating data.

Fix

For each 4XX URL: if the content moved, set up a 301 redirect to the new URL and add the new URL to the sitemap. If the content is permanently gone, return 410 Gone and remove the URL from the sitemap. Regenerate and resubmit the sitemap.

Explain

Explain why sitemaps must only contain live, indexable URLs, how 4XX URLs in sitemaps affect crawl budget allocation, and the difference between 404 and 410 status codes for deindexing.

Code Review

Review metadata generation, rendered HTML, structured data, and response headers related to 4XX Pages in Sitemap. Flag exact routes or templates where search-facing output violates the rule, and describe how to verify the final page output.


For full implementation details, code examples, and framework-specific guidance, see references/rule.md.

Rule page: https://frontendchecklist.io/en/rules/seo/sitemap-4xx

Signals

GitHub stars
74k
Forks
7k
Last commit
Oct 2026

Questions

When should this skill be used?
Use it for any site with a dynamically generated or manually maintained XML sitemap, when investigating crawl errors, or after a site migration that removed pages.
What does it check?
It checks a website's XML sitemap for broken links so the agent can find dead URLs and crawl errors.
Does it work with manually maintained sitemaps?
Yes, it applies to any site with a dynamically generated or manually maintained XML sitemap.
Advanced
Item type
skill
Key
sitemap-4xx
Source
github.com/thedaviddias/front-end-checklist