Goal vs Plan Mode
The destination an agent is working toward, versus a deliberate pause to plan the route
Goal
The target itself: what an agent or a fleet is ultimately trying to accomplish, possibly across many sessions, defined independent of how any one session goes about reaching it.
Plan Mode
A working mode for a single session: the agent researches and proposes an approach without editing any files, so a human can approve the plan before implementation begins. It produces a plan for reaching a goal, it isn't the goal itself.
Which one do you actually need
A goal is where the work is ultimately headed. Plan Mode is a deliberate stop, inside one session, to work out the route before touching anything real. A single goal can pass through several separate rounds of Plan Mode, one per session, before it's actually reached, especially on work that's long-running or genuinely risky.