Friday, August 21, 2026

    Distribute tools appropriately across agents and configure tool choice

    Domain 2 — Tool Design & MCP Integration · 18% of the exam

    Task statement 2.3

    Distribute tools appropriately across agents and configure tool choice

    What you should be able to do
    • Explain why tool-selection reliability degrades as an agent's tool count grows.
    • Scope each subagent to the tools its role needs, with narrow cross-role exceptions for high-frequency cases.
    • Replace a general-purpose tool with a constrained one that validates its own inputs.
    • Use tool_choice "auto", "any" and forced selection, and say what each one guarantees.
    Exam traps (5)

    Give every agent the full toolset so none of them is ever blocked.

    Each additional tool widens the decision, so selection accuracy falls — and agents reach for tools outside their specialisation, like a synthesis agent running its own searches.

    Scope tools to the role. A blocked agent is a routing question for the coordinator, not an argument for a bigger toolbox.

    Set tool_choice to "any" so the model is guaranteed to pick the right tool.

    "any" guarantees that some tool is called, not which one — and it removes the option of answering directly when no tool is needed.

    "any" forces a call; forced selection names the tool. Use forced selection when a specific tool must run first.

    Force the required first tool and let the model handle the rest in the same turn.

    Forcing applies to the request you send it on, so the ordering guarantee does not extend across the steps that follow.

    Force the first call, then process the remaining steps in follow-up turns.

    Route every cross-role need back through the coordinator, for cleanliness.

    A high-frequency check becomes a round trip through the hub every time, which dominates latency for something narrow and well-defined.

    Give a narrow scoped tool for the frequent case; route the complex ones through the coordinator.

    Keep a broad utility tool available because it covers many situations.

    A permissive tool accepts inputs it should refuse, so misuse shows up as plausible-looking output rather than an error.

    Prefer a constrained tool that validates what it is handed over a general one that will accept anything.

    Primary sources
    Know cold
    • Tool distribution
    • tool_choice
    • Least privilege
    • allowedTools

    14 practice questions in the bank are tagged to this task statement.

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