- Chunker: char overlap across boundaries + hard-split of oversized paragraphs. - Retrieval knobs: rag_top_k / rag_min_score in settings + Settings UI. - Vector index: sqlite-vec ANN over document embeddings, dual-written and backfilled, with brute-force cosine as the guaranteed fallback. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>