Components · Agents

Subagent pool

A lead agent fans work out to parallel subagents, each with its own context.

Lesson
Coming soon
Zone
ai
Place it
10 cr on the blank canvas, free inside a problem

At a glance

Did you know
Multi-agent research systems fan a task out to parallel subagents and use many times more tokens than a single agent.
Rule of thumb
Use them for broad, parallel work; give each subagent a clear goal, tools and output format.
Watch out
Token use multiplies with subagents; tools saturate under the fan-out.

Its settings in ScaleMySystems

What you can change on it in the lab, and what each number does.

Concurrency (slots)
Calls it can work on at once (per instance when autoscaling). Needed slots ≈ calls per second × seconds each takes. Extra calls wait in the queue, then are rejected.
Queue capacity
Calls allowed to wait for a free slot. A bigger queue absorbs bursts but adds waiting time; 0 rejects straight away.
vCPU
CPU cores available. Needed ≈ calls per second × CPU per request ÷ 1000. Above about 90% busy it slows down and may crash.
CPU per request (ms)
CPU time each call burns. Part of what the component is; make the code cheaper to lower it.
Latency (p50) (ms)
Typical time one call takes here, before any calls it makes itself. Slots are held for this long.
Latency (p99) (ms)
The slowest 1% of calls. Callers must set their timeout above this or they cut off healthy calls.
Timeout to dependencies (ms)
How long it waits for each call it makes before giving up. Set it above the dependency’s p99 but low enough that a dead dependency does not hold every slot.
Error rate
Share of calls that fail on their own (bugs, declines, flaky tools). An agent that calls it on every step multiplies this.
Quota (req/min)
Calls allowed per minute (an API key or provider limit). Calls over it get 429s. Needed = calls per second × 60, with headroom.
Calls per request (fan-out)
How many times its outgoing calls run per request: agent steps, jobs, subagents. Load on everything behind it is multiplied by this, and any step failing fails the request.

Problems that start with it

  • Subagents swamp the search tool A lead agent fans each question out to 8 parallel subagents, and each subagent searches the web. The search tool has 8 slots.
  • Multi-agent token bill Every subagent sends 3,000 tokens of context. Eight subagents per question multiply token use past the provider quota.
  • Fragile subagents Eight subagents each call a tool that fails 1% of the time; any subagent failure fails the question.
  • Research agents share few browsers A deep-research system fans out to 5 subagents that each browse the web; the browser pool has 16 browsers.
  • Deep research: from launch build to real traffic A multi-agent research product on its first servers: the lead agent fans each question out to sub-agents that search and browse the web, and the browser tool, sub-agent pool and model capacity are an eighth of their real size. Questions arrive one a second and each takes minutes. One in ten fails.

Full lesson coming soon

Lessons are being added one component at a time: how it works, its settings, a live exercise to break and fix it, interview questions and a short check. See the Circuit breaker lesson for what one looks like.