I think that using a harvesting tool should utilize AP. This adds a cost to those who are collecting resources (chopping wood can take energy). If it takes AP then maybe it should generate heat as well.

Possible differences can have different amounts of AP for apprentice tools, journeyman tools and independent tools. Perhaps lower amounts for apprentice tools, higher for journeyman and highest for the independent tools

Maybe viscosity should also influence the tool use as well (though I don't believe that tool use should influence a location's viscosity amount).

Also should a person's resource skill influence the number of action points needed? Maybe the skill amount can only influence the amount added by viscosity.

Comments please.

Number of AP increasing with AD allows older players to venture further into the realm exploring it and preventing young players from going too far from areas where they could learn and train. On the other hand tools are shared and are supposed to be usable by as many ppl as possible (well, thos who can lay hand on them - themselves or asking for help). AP usage cost would have to be either very small (20?)... or would make them inoperative for younger players.
I agree it would be nice to have harvesting skills and tools 'level' matter - but there is cooldown for that. Also, currently byproducts are generated only for 0 in inventory - that could also depend on skill/ tool.