Citations shipping

Trust, but verify.

Citations make Claude's answers verifiable. You pass documents into a message; Claude returns text where every claim is linked to a span of a source document. Users can hover and see exactly where each statement came from. The same primitive powers RAG-style products without the bespoke retrieval plumbing.

Documents in, citations out.

1. Pass each document as a content block of type document with citations.enabled = true.
2. Ask the question as a normal text block.
3. Receive a response where text segments come paired with citations arrays — page numbers, line ranges, or character offsets back to the source.
4. Render in your UI by hyperlinking each cited span back to the source.

What you can ground on.

How users want it.

• Hover footnotes. Tiny [1] superscripts; hover to see the source span.
• Sidebar evidence. Highlight the cited span on the source document beside the answer.
• Confidence by coverage. Show users when a sentence has zero citations — that's a hallucination risk.
• Citation copy. When users copy text, copy the citations too. Useful in legal / academic flows.

Combine.

• Files API — upload large PDFs once, reference repeatedly.
• Prompt Caching — long source docs are perfect cache material.
• Tool Use — let Claude fetch the right document(s) before answering.

Related products.

Every Anthropic surface has its own page on this guide.