Retrieval-Augmented Generation (RAG) means the model answers from your documents — it retrieves relevant passages first, then generates from them, citing where answers came from. You don't need to build a pipeline to understand RAG; you need to run one over your own notes and learn its failure modes firsthand.
Tier: Core · Hands-on time: ~60 minutes
That experience is what this playbook delivers, on a free local stack, with a hosted shortcut included.
Start Open WebUI connected to Ollama.
docker run -d -p 3000:8080 \
-e OLLAMA_BASE_URL=http://host.docker.internal:11434 \
-v open-webui:/app/backend/data \
--name open-webui ghcr.io/open-webui/open-webui:main
Open http://localhost:3000, create the local admin account (stored locally), and confirm your Ollama model appears in the model picker.
Build the knowledge base. In Open WebUI: Workspace → Knowledge → create a collection ("my-notes") → upload your documents. The tool chunks and embeds them locally — this is the "indexing" half of RAG happening on your machine.
Ask with retrieval on. In a new chat, reference the collection (the # collection picker) and ask one of your known-answer questions. Inspect the response's citations panel: which chunks were retrieved, from which files.
Run your 7-question eval. Ask all 5 known-answer questions and both known-absent questions. Score each:
Tune the two levers that matter. If answers miss obvious content: your documents may have poor headings/structure — retrieval works on chunks, so a 40-page unstructured PDF retrieves badly; split it or add headings and re-upload. If it confabulates on absent questions, add a system prompt to the model in Open WebUI:
Answer ONLY from the provided context. If the context does not contain
the answer, reply exactly: "Not found in the provided documents."
Always name the source document for each claim.
Adopt or discard deliberately. Re-run the eval after tuning. If ≥5 of 7 pass, fold it into your routine for that corpus; if not, you've still learned precisely where RAG breaks — which is the professional skill this playbook is actually teaching.
RAG quality is mostly retrieval quality. When the answer is wrong, look at what was retrieved before blaming the model — nine times out of ten the right chunk never reached it.