I don't think that is a good idea because it'll catch dependency cycles, missing injections, and other things at compile time that you would uncover at runtime

Not necessary. Toothpick checks dependency cycles and validates graph even with reflections https://github.com/stephanenicolas/toothpick/wiki/Configurations#runtime-checks

I don't really care, I'd be fine finding that on demand and on release builds

Incremental kapt and multiple modules makes the compile difference negligible. discovering issues at runtime could take longer than compile time

Kapt will never be incremental by default, only Annotation Processor itself, so better to choose AP wisely, but you right now Kapt doesn't support Gradle API for incremental APs

there is a

kapt {
useBuildCache = true
}

which can map input to output and reuse if the input has not changed. That also will allow faster compile with multimodule project. I have a project with 20+ modules that when you make changes that touch a feature module, it only takes about 12-15 seconds to compile.

Do you use that in production?

yeah but on CI we turn off caching and always do a full recompile

But this is not incremental compilation, if class path of module with KAPT changed (so if any class of module or dependency changed) it will be recompiled even with build cache