Intelligence
Intelligence measures reasoning, memory, study, analysis, and the ability to understand systems rather than simply react to them. In some campaigns it is a specialist score; in others it becomes the backbone of investigation, research, and arcane competence.
Scholarly and technical checks. Intelligence tends to lead when the party needs recall, interpretation, planning, or technical understanding rather than force or instinct.
Arcane build support. Some classes cast from Intelligence directly, and even characters outside those lanes may depend on it for magical research, item knowledge, and tactical reasoning.
Investigation and structure. When the adventure turns into “what actually happened here?” Intelligence often becomes the difference between guessing and understanding.
Push it when the class needs it
If the class casts or solves problems through scholarship and structure, Intelligence should feel like a primary score, not incidental flavor.
Let campaign tone guide the floor
In lore-heavy or investigative games, even non-Intelligence-primary characters may want more here than a purely combat-focused table would demand.