Forty to fifty runs a day for under five dollars is a useful counterweight to the cost guides, and it matches what we see: most agent spend comes from design choices, not from the model price list.

The part I would underline is your list of failures that report themselves as something else. A billing error that looks like a rate limit, or a scheduler that quietly stops, costs more than tokens ever will because nobody notices for days. A per-run record of which provider answered, under what limit, and whether the output was used is cheap to build and pays for itself the first week.

When we scope agent work for clients, that run log is part of the definition of done, not a later nice to have.