diff --git a/crates/ailang-check/src/mono.rs b/crates/ailang-check/src/mono.rs
index de3d4fe..00c21af 100644
--- a/crates/ailang-check/src/mono.rs
+++ b/crates/ailang-check/src/mono.rs
@@ -308,20 +308,17 @@ pub fn mono_symbol(method: &str, ty: &Type) -> String {
     format!("{method}__{}", &full_hash[..8])
 }
 
-/// Iter 22b.3: returns the surface name iff `ty` is a zero-arity
-/// primitive `Type::Con`. Used by [`mono_symbol`] to gate the
-/// human-readable form. The match is intentionally narrow:
-/// `Int<args>` (which is malformed but parser-accepting) is
-/// treated as compound, so it falls to the hash form.
+/// Returns the surface name iff `ty` is a zero-arity primitive
+/// `Type::Con`. Used by [`mono_symbol`] to gate the human-readable
+/// form. The match is intentionally narrow: `Int<args>` (malformed
+/// but parser-accepting) is treated as compound, so it falls to
+/// the hash form. The primitive-set itself lives in
+/// [`ailang_core::primitives::primitive_surface_name`].
 fn primitive_surface_name(ty: &Type) -> Option<&'static str> {
     match ty {
-        Type::Con { name, args } if args.is_empty() => match name.as_str() {
-            "Int" => Some("Int"),
-            "Bool" => Some("Bool"),
-            "Str" => Some("Str"),
-            "Unit" => Some("Unit"),
-            _ => None,
-        },
+        Type::Con { name, args } if args.is_empty() => {
+            ailang_core::primitives::primitive_surface_name(name)
+        }
         _ => None,
     }
 }