Shape & gaps
No thin walls
The shape rule considers all your nearby claims together. L, T and small recesses fit; large enclosed pockets, thin U shapes and frames do not.
Enclosing foreign claims is forbidden. Land owned by your guilds and their members counts too. Splitting land does not bypass the rule.
Fill a gap
Select an unclaimed gap with /claim corner1 and /claim corner2. Stand on the matching land you own, then /claim consume.
The gap must touch it and lie inside the rectangle around the land. It may be smaller/narrower than a new claim; budget and foreign protection still apply.