AI-powered Q&A over enterprise document corpuses with citations. **Challenge:** A 200-attorney firm needed to query 50 years of case law without exposing client data to public LLMs. **Approach:** Built on Cloudflare Workers AI + vector search over pgvector; strict data isolation per client; full audit trail. **Outcome:** - 90% answer accuracy on internal test set (vs 65% for naive RAG) - 12 hours/week saved per attorney on average - Zero client data leakage across tenants