What to build: An authenticated "Ask" box: the user types a subject-level question — "what do I have on the history of printing?", "recommend me something unread for a train ride" — and gets an answer grounded in their own Catalogue. Implementation per the design review: one LLM call through the existing OpenRouter setup with the full enriched catalogue (current holdings, slim fields + description/subjects + read status) in the prompt context. No embeddings, no vector store, no index — at household scale the whole catalogue fits in one context window.
Answers should name the actual Volumes they refer to, and honestly say when the catalogue holds nothing relevant. The endpoint spends money, so it must sit behind auth (which is why this is blocked by 01) and apply the same primary/fallback model discipline as scanning.
Blocked by: 01 — Shared-password auth; 07 — Volume enrichment.
Status: ready-for-agent
by title/author; asking about something absent says so plainly
surface as a readable message, not a spinner