The present tool generates reference documentation without the usage of recipes. Currently the following generation is supported.
Docsgen can be built using the command fx build tools/docsgen
For example, you can set it to a minimal configuration:
fx set minimal.x64 --with //tools/docsgen
Then, build docsgen:
fx build tools/docsgen
You can then see the built documentation in the out/default/obj/tools/docsgen directory of your Fuchsia checkout.