What this is

No new concepts in this lesson. This is a checkpoint: everything from Lessons 10 through 17 combined into one small, real assistant. If you can read lesson.py and understand why every piece is there, you've mastered the Intermediate tier.

What it does

The same hybrid retrieval from Lesson 9's Beginner checkpoint, now with three upgrades: the index is persisted to disk (Lesson 13) instead of rebuilt every run, retrieval can be scoped to a category before fusing (Lesson 12), and every answer cites its source, same as naive_rag's own notes-search assistant, just with a hybrid retriever underneath.

Where each piece came from

def load_or_build_store(notes_dir, store_path) -> dict:
    if store_path.exists():
        return json.loads(store_path.read_text())
    store = build_store(notes_dir)
    store_path.write_text(json.dumps(store))
    return store

Lesson 13, unchanged: load from disk if a saved index exists, build and save it if not. Every question this script answers reuses the same loaded index, no repeated embedding calls.

def hybrid_retrieve(query, store, k=2, category=None):
    candidate_indices = [i for i, name in enumerate(store["names"]) if category is None or CATEGORY.get(name) == category]
    ...

Lesson 12's filter, applied before either retriever scores anything, folded into the same function that does dense ranking, sparse ranking, and RRF fusion, Lessons 2-8's full pipeline in one call.

def ask(query, store, k=2, category=None) -> str:
    top_names = hybrid_retrieve(query, store, k, category)
    return generate(query, top_names, store)

The whole pipeline as one function call, same shape as Lesson 9's ask(), now taking an optional category.

Try this yourself

Without looking anything up:

  • Delete store.json and rerun. Does the first run's timing noticeably differ from the cached second run, the way Lesson 13 predicted?
  • Ask ask("20240115", store, category="kitchen"), an ID whose real answer lives outside the category you scoped to. What does it return, and does that match what Lesson 12's filtering logic should do?
  • Reuse Lesson 16's exact question ("What change finally made things work reliably again?") through ask(). Does the generated answer correctly say it doesn't know, or does it guess? Compare that against what Lesson 16 already showed about where the retrieved chunk ranked.

If you can make these changes confidently, you're ready for the Advanced tier, starting at Lesson 19.