Problems / Multi-agent and harness, medium

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.

Free to open. Runs in your browser, no sign-up.

Your goals

Success ≥ 95% of tasks, p99 ≤ 90 s.

The traffic

4 requests a second for 45 seconds: 100% task (writes).

The system

What each component does in this design, and what calls it. The simulator mimics each one from these settings.

ComponentIts job hereSettings
Load balancerLoad balancerTraffic enters here.Calls Agent API.Layer 4 balancers route by IP and port; layer 7 balancers read HTTP and can route by path or header.–
Agent APIApp serviceLoad balancer forwards to it.Calls Agent orchestrator.Little's law: throughput ≈ concurrency ÷ latency. 200 slots at 50 ms serve about 4,000 req/s.3 replicas × 500 slots · timeout 180 s
Agent orchestratorAgent orchestratorAgent API calls it.Calls Model, Subagent pool.An agent loops: think, call a tool, read the result, repeat until done.400 slots · 2 steps
ModelLLM endpointAgent orchestrator calls it.Latency has two parts: time to the first token, then a steady stream of tokens per second.300 streams
Subagent poolSubagent poolAgent orchestrator calls it.Calls Web search tool.Multi-agent research systems fan a task out to parallel subagents and use many times more tokens than a single agent.400 slots · 8 steps
Web search toolTool / MCP serverSubagent pool calls it.Tools give the model actions such as search or database queries; each call is another round trip.8 slots

Hints

Try it first. Open one hint at a time if you get stuck.

Hint 1

Fan-out multiplies tool calls.

Hint 2

Broad questions need many subagents; most don’t.

One way to solve it

Halve the fan-out (or give search more capacity).

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