What problem does it solve? Long-form reference documents like books, whitepapers, and filings sit unread because searching them manually is slow. This Skill ingests epub and PDF files into a semantic vector index so you can ask natural-language questions over your library and get back cited passages with page or section locators. ## Core Features & Use Cases - Document Ingestion: Uploads raw epub/PDF originals to Cloudflare R2, extracts and cleans text (ligature repair, hyphenation fixes, front-matter filtering), chunks into ~400-token windows, embeds locally with BAAI/bge-small-en-v1.5, and indexes into Supabase pgvector. - Semantic Q&A with Citations: Embeds a question, runs the match_doc_chunks RPC, and returns top-k passages with document title, author, and section/page citations for grounded answers. - Retrieval Evaluation & A/B Testing: Ships recall@k acceptance gates, a 25-case validated eval set, a local cross-encoder reranker, and a 3-arm harness (dense, hybrid_rerank, contextual_hybrid_rerank) with an explicit ship rule. - Use Case: Ask "what does Inference Engineering say about KV cache sizing" and receive the relevant passages cited as "Chapter 3 Hardware > 3.1 GPU Architecture" or "p.79". ## Quick Start Ask the assistant to ingest a book from your knowledge library with /ingest-doc and then query it using /ask-library with your question.