AI Agent Engineering Interview, issue 1, Sep 20, 2026
The Meta-Tool Trap
Senior AI Engineer interview at Google, and the interviewer asks:
“Your agent has 70 REST tools and needs 12 sequential calls to compare smartphone prices across 4 countries. Switching to code execution raises success rates and cuts turns. So why isn’t code execution the default for every agent?”
Don’t say: “Because code can have bugs, so JSON tool calls are safer.”
Code execution isn’t just a faster tool call, it's an unvetted runtime that introduces infinite loops, runaway memory, and supply-chain exploits to your host.
The full answer, with the mechanism and the arithmetic, is for paid subscribers on Substack.