prebuilt.loop

agent_loop

agent_loop(...) builds an agent loop and returns it as a Step.

Key parameters:

• body(state, loop_state) -> state
• stop_condition(state) -> bool
• policy: LoopPolicy (iteration limits, checkpointing, budgets)
• name: step/agent name (used in tracing)
• agent_type: type string for agent events

LoopPolicy

Loop execution configuration:

• max_iterations
• timeout_seconds
• checkpoint_store
• checkpoint_policy
• execution_policy (budgets)

LoopState

Per-run loop state passed into the loop body:

• iteration
• start_time
• last_checkpoint_id
• agent_run_id

simple_loop

Convenience wrapper when you don’t need LoopState inside the body.

from coevolved.prebuilt import simple_loop

loop_step = simple_loop(
    body=lambda s: {**s, "n": s["n"] + 1},
    stop_condition=lambda s: s["n"] >= 3,
)

Next steps

Agent loop pattern

Conceptual guide to loops, stop conditions, and policies.

prebuilt.react reference

A concrete loop built on agent_loop: ReAct.