The Power Focus spell list includes the spells "Assess Source" and "Tap Source." I naively assume that a source is the same for both spells. Given that, what is a source?
At one extreme a source might only include "stores" created using Power Storage or Store spells (e.g., from Power's Master). This prevents massive power taps, but makes Assess Source useless (and limits Tap Source's value).
Other possible sources of power might include:
- Deities (although how often are you able to Assess/Tap a deity?)
- Items (they have the equivalent of PPs that recharge over time)
- Spell-casters (this seems inappropriate given Power Merge spells)
- Earth nodes (but these already reduce PP costs, and open up the Power Mastery list)
- Ley lines (would tapping a ley line lead to corruption?)
Note that Tap Source is a U(tility) spell, so it can only be cast on a willing target.
Finally, assuming a fairly standard fantasy setting (Greyhawk in this case), what sort of information should Assess Source provide? If cast on a person, do you get an idea of PPs? Or, can you cast it on an item to get a sense of charges?