modul 2 — the toolbox in depth
subagents: parallel hands
One agent, one context – that's the ceiling of module 1. Subagents break it: delegated workers with their own context that return only the conclusion.
~3 min read · ~11 min with the exercise · v1.1 · verified: 2026-07-15
why one context is a ceiling
Module 1's context lesson taught you to protect the budget: one session, one task, no dead weight. But some tasks produce dead weight by nature: a codebase-wide search dumps hundreds of file excerpts into the conversation, and you'll reference none of them again. The conclusion is one paragraph; the garbage is the other 95%.
A subagent (a delegated agent instance that does a side task in its own separate context and returns only a summary to the main conversation) is the answer. The official docs put it precisely: use one "when a side task would flood your main conversation with search results, logs, or file contents you won't reference again: the subagent does that work in its own context and returns only the summary."