It would be nice to have a tweak that displays an overlay or indicator if that block is spawn-proof. For example Red if it isn't spawn proof; yellow if hostile mobs could spawn on the block; green if only passive mobs could spawn on it; white if its completely spawn-proof

this feature is already in minihud

yeah, that is another mod from masa, some info about it http://curseforge.com/minecraft/mc-mods/minihud

is that another client-side mod?

ok
, thanks