Function merge_same_surface_faces_scoped 

pub fn merge_same_surface_faces_scoped(
    solid: &BrepSolid,
    tolerance: f64,
    keep_unmerged: &[String],
    scope: &FxHashSet<u64>,
) -> Result<BrepSolid, KernelRefusal>

merge_same_surface_faces_excluding whose closing validation reads the geometry of the faces in scope and of the faces the merge built; every pair still merges exactly as the plain call merges it (an operand’s own coplanar neighbours included: the 2026-10-10 census found a mesh import whose five such pairs the boolean fuses). A boolean passes the faces its operation touched and their neighbours (BooleanOptions::untouched_passthrough); the rest were validated by the assembler and left this pass as they came.