Grounding and citation as first-class features

For a domain agent, citations aren't a nice-to-have; they're the product. Design so that:

• The model only asserts what it can ground. Instruct it to base claims on retrieved source content, never on training-data recall, and to refuse or hedge when it lacks a source. "Do not fabricate" is a load-bearing rule, not boilerplate.
• Citations are precise and verbatim. A citation should point to an exact location (page, section, paragraph) and quote the source verbatim, so the expert can confirm it in seconds. Approximate or paraphrased citations defeat the purpose. (This is why tool-based reading with location markers often beats lossy retrieval for these domains, Chapter 7.)
• Citations are machine-checkable. Use an emitted citation protocol (Chapter 6) that your code can parse and validate: confirm the quoted text actually appears at the cited location before showing it. Catching a hallucinated citation automatically is a powerful safety net.
• The UI makes verification effortless. Click a citation, jump to the exact place in the source, see the quote highlighted. Lowering the cost of checking is what makes the agent usable for careful professionals.