A next action is the single visible move that gets motion back into the work: a verb plus enough context to do it later without rethinking everything. In GTD, captures land in an inbox and you process each one. An item with no action is reference, trash, or someday maybe; an item that belongs to someone else becomes waiting on. “Launch the client portal” is a goal. “Email Sam for the DNS login” is a next action.
Clearing a jammed printer shows the difference. “Fix printer” labels the whole problem. “Open the paper tray and remove the stuck page” is a next action: you can see it, you can do it, and after that the next move may change.
Why you care
Most stuck work is stuck because the next visible move is unclear, so people reread the same email and reopen the same note without doing anything. A good next action removes that reload cost and makes delegation cleaner: “Help with the portal” names no action, while “Confirm which domain the portal should live on” creates movement and ownership. The same goes for agents. AI makes progress on a clear step and struggles with a foggy wish.