Route each call to a capable tool, for the least total cost.

A request can only use a tool whose capability ≥ its need. Pick the cheapest tool that clears each request — defaulting everything to the most powerful model burns budget.

Practice — no rating pressure. Get as close to the optimum as you can; each play teaches the pattern.

Total cost

—

0 / 7 routed

request 1 · needs tier 1

request 2 · needs tier 2

request 3 · needs tier 3

request 4 · needs tier 2

request 5 · needs tier 2

request 6 · needs tier 3

request 7 · needs tier 3

Tool Router — practice the decision, scored against the optimum

What does the Tool Router puzzle teach?

Route each call to the cheapest tool that's capable enough — defaulting to the most powerful model burns budget.

Why do interviews ask about this?

Routing a query to the right tool/model is the agent-infra interview — match capability to cost; don’t over-call the expensive one.

How is it scored?

The engine computes the provably-optimal answer for the exact instance you played (dynamic programming, shortest-path, or exhaustive search — never a heuristic) and scores your attempt as a percentage of it. No login needed to see your score.

← Arena

Practice0:00

Tool Router · D5

Route each call to a capable tool, for the least total cost.

A request can only use a tool whose capability ≥ its need. Pick the cheapest tool that clears each request — defaulting everything to the most powerful model burns budget.

Practice — no rating pressure. Get as close to the optimum as you can; each play teaches the pattern.

Total cost

—

0 / 7 routed

request 1 · needs tier 1

request 2 · needs tier 2

request 3 · needs tier 3

request 4 · needs tier 2

request 5 · needs tier 2

request 6 · needs tier 3

request 7 · needs tier 3