Lesson 3: Tool results and errors a model can use
21 min read·13 Oct 2026
Module 3 · Lesson 3 · About 45 minutes · Needs: Lessons 1 and 2 of this module (tools, output schemas, annotations); Module 2 (JSON-RPC error responses)
The situation
Tuesday 15 September 2026, the afternoon. This morning Nare saved her consent form draft as the note nap-study-consent-form. Now Priya has approved the final wording, and Nare types: "Save my revised consent form as a note." The model calls create_note with the title "Nap study consent form". That id is taken, and the store never overwrites.
What comes back decides what happens next. A message the model can read lets it pick a new title; a failure only the host sees leaves it guessing. This lesson follows that call, and a search before it, through every kind of result and error.