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Agent LighthouseAgent Lighthouse

    Searches the text of every published page. The evidence sources themselves are not in this index — search all of them on the trusted sources page.

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    structured-data/breadcrumb-schema

    BreadcrumbList schema

    What it checks

    Common scope replaces the page-type list and URL-depth test. Existing BreadcrumbList markup or a visible breadcrumb-labelled container with at least two steps selects a page. The visible trail must include a link. Class, id and aria-label breadcrumb tokens are recognized; hidden trails and lone home links do not establish the feature. All relevant pages with markup pass; mixed coverage warns; observed trails without markup fail; no feature returns NA.

    Why it matters

    Grade A and weight 1 remain tied to Google Search, not to an undocumented AI navigation path. Google recommends typical user paths rather than mirroring URL structure (verified 2026-10-21). A visible trail supplies independent evidence of hierarchy, including on a flat URL.

    Evidence

    Mechanism claim: Google Search parses BreadcrumbList markup in the body of a page and uses it to categorize that page and render a breadcrumb trail in the search result, in place of the raw URL.

    • Google: “Google Search uses breadcrumb markup in the body of a web page to categorize the information from the page in search results.” Required shape: an itemListElement array; each ListItem requires position (“Position 1 signifies the beginning of the trail”), name and item (item “is not required” for the last element) — developers.google.com/…/breadcrumb (verified 2026-08-21)
    • Breadcrumb remains a live feature in Google’s structured data gallery: “Navigation that indicates the page’s position in the site hierarchy.” — developers.google.com/…/search-gallery (verified 2026-08-21)
    • Adoption: BreadcrumbList found on 6.2M domains in the October 2024 Common Crawl, and on 5.66% of mobile pages — webdatacommons.org/…/stats.html and almanac.httparchive.org/…/structured-data (both verified 2026-08-21)

    Counter-evidence: The audit’s stated mechanism — that AI agents use BreadcrumbList to “navigate between parent/child pages” — has no documented consumer; no LLM or assistant vendor names BreadcrumbList, and Apple’s Applebot type list does not include it. Google’s own guidance contradicts the audit’s URL-depth applicability gate: “We recommend providing breadcrumbs that represent a typical user path to a page, instead of mirroring the URL structure.” Google also disclaims any special schema requirement for AI Overviews and AI Mode — developers.google.com/…/ai-features (verified 2026-08-21). A controlled fetch test found that data present only in JSON-LD was read by 0 of 5 AI systems on direct retrieval — searchviu.com/…/schema-markup-and-ai-in-2025-what-c… (verified 2026-08-21)

    Limits

    This remains a markup-presence check, not full validation of ListItem fields, positions, URL resolution or agreement with the visible trail. JSON-LD graphs, arrays, array types and gathered microdata/RDFa remain supported. A localized or custom trail without a breadcrumb token may remain undetected; arbitrary URL depth does not fill that gap.

    How it scores

    A vendor doc names the consumer (Google Search), states the behavior verbatim, and specifies the required shape of the signal; adoption is at web scale.

    Sources