Use accurate sitemap update dates

What does this finding mean?

The report identifies this check as no-sitemap-lastmod in Freshness and hygiene. The category carries up to 10 of the 100 rubric points. This is a category weight, not an automatic deduction for this finding. Read the scan detail for the measured state, overlapping signals and any score cap.

Add lastmod only when the build can report real substantive changes. Omit it rather than setting every URL to today.

Why does this matter for AI retrieval?

Canonical URLs and valid dates describe which document this is and when it changed. HTTPS protects delivery. These are observable document signals, not a measurement of how often ChatGPT, Claude, Perplexity or Gemini visits.

How do I check and resolve it?

1. Check the sitemap URL in robots.txt and the response at /sitemap.xml. A sitemap index must point to valid child sitemaps.
2. Publish XML containing canonical, public URLs. Replace the example date with the actual substantive update date, or omit lastmod.
3. Return application/xml or text/xml with HTTP 200. Exclude redirects, login pages and noindex routes.

Adapt the example to the reported issue and the actual route. Placeholder names, URLs and dates must be replaced with facts from your site.

Copy code

<?xml version="1.0" encoding="UTF-8"?>
<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
  <url>
    <loc>https://example.com/guide/</loc>
    <lastmod>2026-10-18</lastmod>
  </url>
</urlset>

Verify the result

Fetch the sitemap and a sample of listed pages. Each loc should resolve to the intended public canonical URL. Rescan to check discovery.

Open the related tool or technical guide, then run a new scan of the affected URL. Keep unknown checks marked unknown until you have a complete response.

Copy a prompt for your coding agent

Paste this into Codex, Claude Code or Cursor from your own repository. Include the scan's exact URL and detail so the agent can verify the observation.

Copy prompt for coding agent

Investigate the scanner finding "Use accurate sitemap update dates" (no-sitemap-lastmod) in this repository.
Observation: The sitemap lacks the optional lastmod value checked by this diagnostic.
Required change: Add lastmod only when the build can report real substantive changes. Omit it rather than setting every URL to today.
Inspect the existing route, shared layouts and configuration first. Confirm the finding against the actual response before editing. Preserve intentional access restrictions, existing content and unrelated changes. Use only factual identity and date values. Make the smallest appropriate fix, verify the deployed HTML or resource response and run the relevant project checks. Explain any measurement that remains unknown. Do not promise search rankings or AI citations.
Reference: https://letthebots.in/fixes/no-sitemap-lastmod/