How it works
Claude (Anthropic's frontier model) gains web-retrieval capability when configured with its web_search tool. Behavior: model decides per turn whether to fetch; if so, queries are dispatched to a retrieval system; results are read and synthesized into the response. Anthropic publishes that retrieval uses ensemble cosine + BM25 + authority + recency. Claude is known for being more conservative in its citations: preferring fewer but more authoritative sources, and explicitly avoiding hallucinated facts when retrieval coverage is sparse.
Signals it weights heavily
- Structural depth (H2 hierarchy)
- Author bylines + credentials
- Outbound citations to primary sources
- JSON-LD presence
- Page content density
How to optimize for Claude (with web tool)
- Allow ClaudeBot + Claude-Web explicitly in robots.txt.
- Invest in structural depth: Claude rewards H2-segmented content over wall-of-text.
- Cite primary sources inline (Claude weights outbound-authority-links highly).
- Strong author E-E-A-T moves the needle more on Claude than ChatGPT.