Lesson 4: Tool design: how many tools, safe retries, changing lists

Module 3 · Lesson 4 · About 40 minutes · Needs: Lessons 1 to 3 of this module (search_notes and create_note, annotations, ToolError); Module 1 Lesson 3 (in-memory clients)

The situation

Tuesday 15 September 2026. Nare types: "Save a note titled 'Nap study consent form': draft due 15 September, tag it meeting." The server from Lessons 1 to 3 can do that with one create_note call.

Three design questions sit behind that save. How many tools should the server offer, when the model reads all of them before it acts? What if the reply is lost and the host sends the call again? And how does a client learn that a new tool appeared mid-conversation? This lesson follows the consent form through all three.