loop

Execution Loop (L*)

L* is Loom's internal execution loop. It is the engine behind Agent.run(), Session.run(), and Run.wait().

Phases

L* = (Reason -> Act -> Observe -> Delta)*

Phase	What happens
Reason	build messages, call the model, interpret next step
Act	execute tool calls and safety checks
Observe	feed results back into runtime context
Delta	decide whether to continue, renew, or finish

Public Mapping

Public API	Internal loop effect
agent.run(...)	starts one L* execution
session.run(...)	starts one L* execution with session reuse
run.events()	streams runtime events emitted during L*
RunResult	materialized output after L* exits

Related Config

L* behavior is controlled indirectly through:

• RuntimeConfig.limits
• RuntimeConfig.features
• Generation
• HeartbeatConfig
• SafetyRule

Internal Code

• loom/runtime/loop.py
• loom/runtime/engine.py