Lesson 2: Fewer, safer tools: designing the tool surface
32 min read·13 Oct 2026
Module 3 · Lesson 2 · About 60 minutes · Needs: Lesson 1 (tool definitions, run_tool, actionable errors)The situation
It is Friday 1 May 2026, week 3. Dev reviews your first tool list: fifteen tools, one per backend endpoint, such as orders_get, labels_create and email_send. "Every rule I care about sits between two of them," he says.
You trace Aisha's R-1001 again: the RoboSweep X2, order 5521, $129.00, 18 days after delivery. The fifteen tools become the course's eight, and the eight become hard to misuse, safe to retry and cheap to read.