---
title: sitemap entries include <lastmod>
description: "<lastmod> lets agents do incremental re-ingestion — they can skip pages whose lastmod hasn't changed since their last crawl. Without it, agents either re-fetch everything every time (wasteful) or never update their snapshot (stale)."
doc_version: 0.2.0
last_updated: "2026-04-24T21:30:56.217Z"
---

## How the check decides

After parsing the sitemap, the check inspects every `<url>` entry and counts how many are missing a `<lastmod>` child. Passes if all entries have one. Fails with a count if any are missing. Warns if the sitemap has zero entries. Returns N/A if the sitemap couldn't be parsed at all.

## How to implement it

Most sitemap generators emit `<lastmod>` automatically from the source file mtime or the content's `last_updated` frontmatter. If yours doesn't, populate it from the most recent commit touching each page.

### Pass

```xml
<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
  <url>
    <loc>https://example.com/docs/install</loc>
    <lastmod>2026-04-01</lastmod>
  </url>
</urlset>
```

### Fail

```xml
<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
  <url>
    <loc>https://example.com/docs/install</loc>
  </url>
</urlset>
```

## Sitemap

Full docs site index: [/sitemap.md](/sitemap.md).