For example, say you want to search for bugs in 100 code files. Ask Claude to “use subagents to look for bugs across these files” and it will likely spin up 5 agents, each taking a different section of the codebase. Theoretically in the limit case this is 5x faster than Claude doing it without subagents.

Any kind of problem shaped like map reduce can be accelerated this way: Looking through your banking records, searching through a database, asking Claude to find that one weird file you remember from three years ago but forgot where you saved it, etc.

Just know that there’s no quicker way to hit your limits than to use subagents. So use them if it’s paid for by your work or whenever you need the 5x speed boost.

You can tell it to do so, but what you'll find is it knows to do it when it needs to. This is another case of "don't overthink it". Just let your agent decide when spinning up sub-agents makes sense.

If you focus too much on optimization, and you do so in the wrong ways, you'll actually find you saved no time/money/tokens vs just letting it decide when to do it. This applies as much to Agentic engineering as it did with programming pre-AI.

tl;dr it will literally do it for you, and it'll tell you when it does so

You tell it to spin up subagents, they do whatever the parent told them to do, usually a segment of a task you gave it.

"use subagents as applicable" (and maybe "use sonnet for simpler tasks")