Schema confirmation used to be a click for every upload. The system would suggest "I think this column is your ID and this one is your vector," and you'd click confirm. Felt useful when I was building it. Felt friction-y 3 months later, when 80% of the suggestions were obvious.
Tightened it: if id_candidates is exactly 1 and vector_candidates is exactly 1, take it. Manual confirm preserved for the ambiguous case (two columns that could be the ID, two columns that could be the vector). The slow-and-careful path was the right default when the system was new and I didn't trust the detector. Now it's a tax.