On July 30, OpenAI cut GPT-5.6 Luna to $0.20 per million input tokens and $1.20 per million output — down from $1 and $6. An 80% cut. Azure matched it on August 1.
We did what most teams did with that news: nothing. Our gateway sent every request to the strong model, because it always had, and because "just use the cheap model" sounds like a decision that comes back as a support ticket three weeks later.
Then someone put the bill next to the traffic mix, and the awkward part was obvious. The overwhelming majority of our requests were title this thread, summarise this diff, extract the fields from this form, name this file. We were paying frontier prices to generate three-word document titles.
Here's what we shipped instead. It's about forty lines of Go, it moved 81% of requests off the expensive model, and it cut the bill by 71%.
It also broke four things, and those are the interesting part.
