A Billion Token Lesson: Because You Can ≠ You Should

Agent Autopsy, Day 6

Last week I spent a weekend building a product nobody asked for.

I didn't catch it in time. Let me tell you how it happened.

The trap

Nicolas Fränkel published a piece on designing teams of AI agents — specialist subagents that collaborate on software engineering tasks. Planner, challenger, coder, tester. Each with a focused system prompt, each with limited tools, orchestrated through a skill.

It's good work. I read it and immediately thought: we should build this for SPFx.

A TypeScript specialist harness. Four agents — Architect, Scaffolder, Builder, Verifier — in a deterministic pipeline. Zod-validated handoffs between them. Compliance injected at build time, not bolted on after. Terminal CLI, BYO token, no desktop app.

I had the architecture designed in 15 minutes. The pipeline spec. The agent system prompts. The handoff packet schema.…