The pattern and Repeat paragraph in docs/mcp.md said that every omitted
or null param keeps its default. pattern.options and
object.repeat.options keep the pattern's or the repeat's current value
instead (except the brick offset, which a brick tileType or gridType
without brickOffset sets to 0.5), object.pattern.edit and
pattern.options fall back to the selected object's pattern and the
pattern being edited when name is omitted, and pattern.delete requires
name.