A flow that silently drops a value can throw off a unit count or a setback before you notice. The Status output tells you exactly when and why that happened, node by node, instead of only downstream where the flow's final result comes out wrong.

Any flow node with both inputs and outputs carries a Status output, labeled S on the node. It reports whether the node's calculation succeeded, completed with a warning, or failed with an error. When a node has a warning or an error, its Status output also carries a message describing what went wrong.

Turn on Inspect Flow (also called Hypersonic Mode). Select the single geometry with this flow assigned to it first. Giraffe only evaluates the flow live for one geometry at a time. See Inspecting a Flow.

Connect a Reader node to the Status output you want to check.

The Reader prints the status as an object, with a type of success, warning, or error, and a message when there is one to show.

With Inspect Flow turned on, a node turns red when it has an error and orange when it has a warning. Hover the node's title to see the message directly in a popover, without connecting a Reader node.