XML Sitemaps have been a staple of SEO for two decades. However, LLMs and AI agents ingest data differently than traditional crawlers. The scale of ingestion for training runs (e.g., Common Crawl) requires a more robust approach.

The Importance of lastmod

For AI models, freshness is a critical signal for reducing perplexity and preventing hallucinations. A sitemap with accurate, high-frequency lastmod tags is essential. It signals to the ingestion pipeline that new training data is available.

The XML sitemap was invented in 2005. It lists URLs. But as we move towards Agentic AI, the concept of a “page” (URL) helps human navigation, but constrains agent navigation. Agents want actions.

The API Sitemap

We propose a new standard: the API Sitemap. Instead of listing URLs for human consumption, this file lists API endpoints available for agent interaction.

<url>
  <loc>https://api.mcp-seo.com/v1/check-rank</loc>
  <lastmod>2026-01-01</lastmod>
  <changefreq>daily</changefreq>
  <rel>action</rel>
  <openapi_spec>https://mcp-seo.com/openapi.yaml</openapi_spec>
</url>

This allows an agent to discover capabilities rather than just content.