Column mapper

The step where a model matches an imported file's columns to your fields. One line per column says where it goes and how sure the match is, and unsure matches are flagged to check. Open a line to see its values and why it was matched, then send it elsewhere or leave it out. Streams the model's matches as they arrive, matches by header and values on its own without one, and ships the prompt and JSON schema for AI SDK Output.object.