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mellea.stdlib.frameworks.react

ReACT (Reason + Act) agentic pattern implementation.

Provides the react() async function, which drives a tool-use loop: the model reasons about a goal, selects a tool, receives the result as an observation, and repeats until it calls final_answer or the loop_budget is exhausted. Accepts any list of AbstractMelleaTool instances and a ChatContext for multi-turn history tracking. Raises RuntimeError if the loop ends without a final answer.

Functions​

FUNC react ​

react(goal: str, context: ChatContext, backend: Backend) -> tuple[ComputedModelOutputThunk[str], ChatContext]

Asynchronous ReACT pattern (Think -> Act -> Observe -> Repeat Until Done); attempts to accomplish the provided goal given the provided tools.

Args:

  • goal: the goal to be accomplished or the question to answer
  • context: the context being used; a type of ChatContext
  • backend: the backend used to generate the response.
  • format: if set, the BaseModel to use for constrained decoding.
  • model_options: additional model options, which will upsert into the model/backend's defaults.
  • tools: the list of tools to use
  • loop_budget: the number of steps allowed; use -1 for unlimited

Returns:

  • A (ModelOutputThunk, Context) if return_sampling_results is False, else returns a SamplingResult.

Raises:

  • RuntimeError: if the loop ends before a final answer is found