Where we left off

Lesson 5 built a complete loop and ran it on a question that needed retrieval. This lesson runs the identical loop, unchanged, on a question that doesn't (general chemistry knowledge), specifically to show the branch that Lesson 5's if not calls: line was written for but never actually exercised, until now.

The misconception this lesson corrects

A very natural assumption, especially after Lessons 3-5 spent so much effort wiring up a tool call, is that declaring a tool makes the model use it. It doesn't. types.Tool(...) makes a function call available, one option among "answer directly" and "request a call." The model still has to judge, per question, whether calling it would actually help. This lesson's gold-symbol question is deliberately something Gemini already knows cold, letting you watch that judgment land on "no" instead of just asserting it can.

The code, piece by piece

def ask(query: str, store: list[dict]) -> tuple[str, bool]:
    ...
    calls = response.function_calls
    if not calls:
        return response.text or "", False

Nothing changed from Lesson 5's ask() except the return type, adding a bool so main() can report whether search_notes() actually ran. The branch itself, if not calls: return response.text, already existed in Lesson 5, this lesson is the first time a question actually takes it.

Checkpoint

  • Declaring a tool makes a call possible, not mandatory, the model still judges whether a specific question needs it.
  • The same ask() function, unmodified, correctly handles both "needs retrieval" and "doesn't need retrieval" questions, because the branching happens inside Gemini's own decision, not in this course's code.
  • Try this yourself: write three more questions of your own, one clearly general knowledge, one clearly about the fixture notes, and one deliberately ambiguous (for example, "What's a good way to keep something from drying out?", which could plausibly be about the sourdough starter or just general advice). Run all three through ask(). Does the ambiguous one go the way you expected?

If anything here still feels unclear, ask before moving to Lesson 7.