Building RAG with LangChain & Chroma: Two Hidden Pitfalls That Cost Me 6 Hours

At 10 PM, my product manager dropped 200 PDFs in my lap: “We need to demo an internal knowledge base Q&A for the boss tomorrow morning—super urgent.” I thought, “RAG? I know this; LangChain plus a vector database, done in minutes.” I started coding at 4 PM and barely finished by 10 PM—not because th