Guides

The tutorials show you how. These explain why, and are meant to be read out of order when a particular question comes up.

Coming from PennyLane	Borrow the three loops worth borrowing without migrating anything, the name map, and the four places the two libraries genuinely differ
The parameter-shift rule	Why the famous two-term formula is not the whole story, and how qmlkit derives a rule per gate instead of transcribing one
Choosing a gradient method	Six options, a decision table, and measured costs
Backends and conventions	Endianness, controlled-gate ordering, precision floors, and three upstream discrepancies worth knowing about
Running under noise	Mixed-state backends, why noise never picks a simulator for you, and what a noise model does to a gradient
Extending qmlkit	Adding a gate, an ansatz, a gradient estimator or a backend — every extension point is a registry
Evaluating a model honestly	Metrics that say when they mislead, skewed classes, the classical bar, and whether a number can be trusted or reproduced
Watching a run	A live line with an honest ETA, what the run spent its time on, and the whole thing written out as one self-contained page
Working with a coding agent	Why a wrong name answers with the right one, and what diagnose() catches that nothing raises for

For how any of this is known to be correct, see Validation.