I'm not sure what to recommend for the undefined action tag. The questions all seem to have something in common and "action" is probably the best single word to describe the concept they share. If this is a useful catchall tag, I'm having trouble with what the definition should be. Maybe:
"Questions involving specific stuff that happens. If your question involves general stuff that happens, it is off-topic for this tag. If your question involves stuff that doesn't happen, use the [brick] tag."