We built our first "multi-agent system" by accident. What started as a single agent that could research a topic, draft a report, check it against source data, and send a summary email had grown into a 2,000-token system prompt and a function list so long that the model kept forgetting tools existed. It wasn't a system — it was a monolith pretending to be intelligent. Breaking it apart into coordinated agents fixed most of the problems. It also introduced a new category of problems we hadn't t...