Step 1 of 82 · Host app → Modeltask + 5 toolsTurn 0 of 12 · context 0 of 3,000 tokens · 0 tokens in all

Chapter 6 of 7

Sub-agents, and the cost of a handoff

In chapter 5 one agent carried all five storm orders in one history, and the host had to compact it, with care, to make it fit. The five orders have nothing to do with each other. So the support lead asks: why should one agent hold them all at once?

This chapter: When should an agent hand parts of a case to helpers, and what does each handoff cost?

You will learn

How a lead agent hands one piece of a case to a helper with a clean context
Why the lead’s context stays small: it gets back one line per helper, not the helper’s whole history
Why the total grows anyway, and when helpers are worth it

Words you’ll meet (4)

Sub-agent: A second agent the host starts for one piece of a case. Larkspur’s team calls it a helper. It has its own history and its own turns.
Lead agent: The agent that works the whole case and hands pieces of it to helpers.
Delegate: The host’s own tool for handing a piece to a helper. The lead calls it like any other tool; the host runs a helper, not a server.
Handoff: Passing a piece of work to a helper. The helper starts again from the instructions and the tools, which costs tokens.

The picture on the left is live. Each step below asks you to do one thing in it; the story continues here as you go.

Step 1 of 5

Monday’s storm again: five damaged orders, 2101, 2102, 2103, 2104, 2105. In chapter 5 one agent held all five in one history, and the host had to compact it, with care, to fit. The host can also offer the agent a tool of its own, delegate: the agent hands one order to a helper, a second agent that starts with a clean context, works that order alone and replies with one line. The agent that hands work out is the lead. Before you run it both ways:

The same five storm orders, two ways. Which setup uses more tokens in total, helpers included?

The case

The task

Monday’s storm soaked a delivery van. Five customers say their orders arrived damaged: 2101, 2102, 2103, 2104 and 2105. For each one, ship a replacement if we have stock, otherwise refund it, and email the customer.

The agent’s tools

get_order, check_stock, create_replacement, issue_refund, send_email, and with helpers on, delegate

What a helper is asked

Order 2101 arrived damaged in Monday’s storm. Ship a replacement if we have stock, otherwise refund it, then email the customer. Reply to the lead in one line.

The host’s rules

Full memory, as in chapter 5: every result stays in the history. A helper has its own history; the lead gets back only its reply.

Sub-agents work in parallel, each with its own context window, which compresses what the lead agent has to hold. Source: www.anthropic.com (checked 2026-10-20)