The API returns passages and document positions along with the response. Understand verifiability, costs, limits and product design.
Direct answer
Anthropic's Citations feature allows you to send documents or search results and receive, interspersed with the response, blocks that point to supporting passages. This improves verifiability and reduces the need to ask the model to invent citation formats. The documentation itself warns that citations cannot be combined with strict structured JSON in the same response and that the final quality still depends on the sources, the documentary excerpt and the review of critical statements.
Useful quote points to evidence
A generic link is not enough. The exact passage allows the reader or reviewer to check whether the statement actually follows from the document.
Bad font keeps producing bad response
Citations improve traceability, not the authority of the material. Origin, date, version and completeness of the document remain essential.
Architecture must separate format and evidence
Because citations and strict JSON output are incompatible, products can use different steps: structured extraction, cited synthesis, and final validation.
Cost must be measured per document
Chunking and instructions elevate input, while cited_text does not count as output. Document caching can reduce repetition when the flow is stable.
Nexus Reading
Citable answers need to be born from governed sources, not from bibliographic decoration. Evidence, permission, version, and revision trail form the trusted product.
FAQ
Does the citation guarantee that the statement is correct?
No. It facilitates verification, but the source may be wrong or the model may interpret the excerpt inappropriately.
Does it work with PDFs?
The documentation accepts documents and offers positions per page or block depending on the type of source.
Can I use citations with structured JSON?
Not in the same answer with strict schema; the API returns an error due to format incompatibility.
Essential guides to delve deeper into the decision
This editorial analysis was produced by Nexus from the official sources below, consulted on September 21, 2026. The text is original and interprets practical implications for companies.
- Anthropic — Quotes: source types, cited blocks, positions, costs, compatibility and examples.
- Anthropic — API and data retention: retention and eligibility of resources used in business document flows.
Date reported by main source: official documentation consulted on September 21, 2026; technical analysis.