# Discoverability

Can an agent find the site's pages at all?

The inventory layer: which URLs exist, which address is the authoritative one, and what a response says about itself before anything parses its body. These are the oldest and most widely adopted technologies we check, which is exactly why the failures here are implementation mistakes rather than gaps.

| Technology | What it is | Adoption | Status |
|---|---|---|---|
| [Canonical URL](/docs/discoverability/canonical) | Tells an agent which address is the real one for this page. | Web baseline, ► flat | scored |
| [HTTP Link header](/docs/discoverability/link-header) | Relations declared in headers, readable without parsing the body. | Web baseline, ► flat | scored |
| [XML sitemap](/docs/discoverability/sitemap) | The URL inventory agents and crawlers use for discovery. | Web baseline, ► flat | scored |
| [llms.txt](/docs/discoverability/llms-txt) | A hand-written index of a site's most useful pages, written for language models. | Early production, ► flat | watched |