Support Anthropic tool result citations

[jerry-reevo]

Description

Anthropic has just introduced a new API for citing search result content from custom backends. This is great for RAG applications that return search result data in tools.

References

https://docs.anthropic.com/en/docs/build-with-claude/search-results

[DouweM]

@jerry-reevo Thanks for filing the issue, that's would be a nice feature to support. I assume you'll want to both be able to use search results as tool return values and top level content, and read citations from the response?

The minimal version of this that we could do pretty quickly (while this is in beta) would be to special-case BetaSearchResultBlockParam tool return values and pass them verbatim to the Anthropic API, in addition to giving you a way to opt-in to beta features by name. Proper support would require our own SearchResult dataclass that would also work with other providers once they add such a concept. Similarly, we could add TextPart.vendor_metadata for now with the raw citations dict returned by Anthropic, but proper support would require our own Citation dataclass that's generic enough to work with other future implementations. I'd prefer to wait to add those until this feature is out of beta, though, as the spec is still subject to changes.

[jeffhodsdon]

+1 here!

I would love to specify the call to use their web search tool —

https://docs.anthropic.com/en/docs/agents-and-tools/tool-use/web-search-tool

[Adarshthakur-850]

Anthropic's new API lets you pass custom search results to Claude, and it will cite them in its response. This is perfect for RAG apps — it improves accuracy, adds references, and reduces hallucination.
A user question
Your own search results (title, URL, content)
Claude replies with:
An answer grounded in those results
Proper citations

[DouweM]

We're open to PRs for this feature, especially now that OpenAI also supports url_citation annotations: #2194, meaning we can define our generic representation that captures both implementations.

[DouweM]

Gemini has citations too: https://ai.google.dev/gemini-api/docs/google-search#attributing_sources_with_inline_citations