Skip to main content
loop: repeats a single node until its own typed output says to stop. It is a do-while loop: the node runs once, then pflow evaluates the condition. 
### wait
- type: workflow
- workflow: ./check-status.pflow.md
- inputs:
    job_id: ${job_id}
- loop:
    until: ${wait.done}
    max_iterations: 60
Use exactly one condition:
  • while: ${node.more} continues while the value is truthy.
  • until: ${node.done} continues while the value is falsy.
Conditions must be single template references to typed outputs. Put comparisons inside the loop body and output a boolean.

​
Carried State

Use carry: when the next iteration needs state produced by the previous one. The node’s inputs: are the round-1 seed. On round 2 and later, carry: overrides only the carried keys. 
### run-rounds
- type: workflow
- workflow: ./judge-round.pflow.md
- inputs:
    contenders: ${initial_lineup}
- loop:
    carry:
      contenders: ${run-rounds.survivors}
    while: ${run-rounds.more}
    max_iterations: 100
Each carry: value must reference this loop node’s latest output. A missing or typoed carried output is a runtime error even when template resolution is permissive — the error names the loop node and its available outputs. A literal coalesce fallback breaks that guarantee, so avoid it in carry:. With carry: { contenders: ${run-rounds.survivors ?? []} }, the [] always resolves, so a round where the body omits survivors silently re-seeds contenders to [] instead of erroring. Validation warns when a carry value uses a literal fallback. A round-1 default belongs in inputs:, not in a carry fallback. For shell and llm nodes, carried keys are effective only when referenced in command, prompt, or system text. Code and workflow nodes consume inputs: directly.

​
Caps And Inspection

max_iterations is optional and defaults to the visit guard. Hitting the cap is not a failure; pflow stamps loop_stopped: "max_iterations" on the loop output. A condition stop stamps loop_stopped: "condition". --only <loop-node> runs exactly one iteration with round-1 seed inputs. It does not reproduce a mid-loop carried state.