Config parameter common.cadHarvestLevel doesn't work. Even if I set it to 0, I'm still able to mine diamonds with Block Break spell:

Spell for testing:
{modsRequired:[{modVersion:"r1.2-80",modName:"psi"}],spellName:"Break Block",uuidMost:-4332167290150632874L,validSpell:1b,spellList:[{data:{params:{_target:2},key:"psi:operator_entity_look"},x:4,y:3},{data:{key:"psi:selector_caster"},x:4,y:4},{data:{params:{_position:2},key:"psi:trick_break_block"},x:5,y:2},{data:{params:{_ray:3,_max:0,_position:2},key:"psi:operator_vector_raycast"},x:5,y:3},{data:{params:{_target:3},key:"psi:operator_entity_position"},x:5,y:4}],uuidLeast:-8295298671943211273L}

P.S.: It's a pity modpack makers doesn't really have an ability to nerf Psi even a little.