Count the knobs on a single transformer block — tile shapes, memory layouts, fusion boundaries, scheduling policy, precision per tensor — and the product runs past 10¹⁷ configurations before you have left the first layer.
Why exhaustive search and pure heuristics both fail
Exhaustive search is obviously out. Fixed heuristics — the traditional compiler answer — are out for a subtler reason: they encode the hardware and model shapes that existed when they were written, and both change every few months.
What we do instead
The harness treats the space as a search problem with a measured objective and a correctness gate. Proposals come from a model that has read the profile; every proposal is compiled, run, and checked against reference numerics before its throughput counts for anything.