diff --git a/crates/ailang-core/src/workspace.rs b/crates/ailang-core/src/workspace.rs
index 5122344..24cf249 100644
--- a/crates/ailang-core/src/workspace.rs
+++ b/crates/ailang-core/src/workspace.rs
@@ -956,6 +956,45 @@ mod tests {
             eq_instance_types.contains(&"Str"),
             "prelude must contain `instance Eq Str`; saw Eq instances on: {eq_instance_types:?}"
         );
+
+        // Iter 23.3: prelude also ships the `Ord` class plus three
+        // primitive instances (Ord Int, Ord Bool, Ord Str). Ord
+        // extends Eq (Decision 11 single-superclass closure), so its
+        // shape is the same as Eq's instance set; the loader uses the
+        // superclass walk to verify the Eq instances exist.
+        assert!(
+            prelude.defs.iter().any(|d| matches!(
+                d,
+                crate::ast::Def::Class(c) if c.name == "Ord"
+            )),
+            "prelude must contain Ord class def"
+        );
+        let ord_instance_types: Vec<&str> = prelude
+            .defs
+            .iter()
+            .filter_map(|d| match d {
+                crate::ast::Def::Instance(i) if i.class == "Ord" => {
+                    if let crate::ast::Type::Con { name, .. } = &i.type_ {
+                        Some(name.as_str())
+                    } else {
+                        None
+                    }
+                }
+                _ => None,
+            })
+            .collect();
+        assert!(
+            ord_instance_types.contains(&"Int"),
+            "prelude must contain `instance Ord Int`; saw: {ord_instance_types:?}"
+        );
+        assert!(
+            ord_instance_types.contains(&"Bool"),
+            "prelude must contain `instance Ord Bool`; saw: {ord_instance_types:?}"
+        );
+        assert!(
+            ord_instance_types.contains(&"Str"),
+            "prelude must contain `instance Ord Str`; saw: {ord_instance_types:?}"
+        );
     }
 
     #[test]
diff --git a/examples/prelude.ail.json b/examples/prelude.ail.json
index 190ecef..9808c72 100644
--- a/examples/prelude.ail.json
+++ b/examples/prelude.ail.json
@@ -118,6 +118,106 @@
           }
         }
       ]
+    },
+    {
+      "kind": "class",
+      "name": "Ord",
+      "param": "a",
+      "superclass": { "class": "Eq", "type": "a" },
+      "doc": "Total ordering. Ships in milestone 23 alongside Eq. `compare x y` returns LT, EQ, or GT (the three-ctor Ordering ADT also in the prelude). Decision 11's single-superclass closure requires `instance Eq T` for every `instance Ord T` — the three Ord instances below pair with the three Eq instances shipped in iter 23.2.3.",
+      "methods": [
+        {
+          "name": "compare",
+          "type": {
+            "k": "fn",
+            "params": [
+              { "k": "var", "name": "a" },
+              { "k": "var", "name": "a" }
+            ],
+            "param_modes": ["borrow", "borrow"],
+            "ret": { "k": "con", "name": "Ordering" },
+            "effects": []
+          }
+        }
+      ]
+    },
+    {
+      "kind": "instance",
+      "class": "Ord",
+      "type": { "k": "con", "name": "Int" },
+      "doc": "Ord Int. The lambda body shape is a placeholder for round-trip stability; the codegen intercept `try_emit_primitive_instance_body::\"compare__Int\"` emits a three-way `icmp slt` / `icmp eq` branch ladder constructing LT / EQ / GT.",
+      "methods": [
+        {
+          "name": "compare",
+          "body": {
+            "t": "lam",
+            "params": ["x", "y"],
+            "paramTypes": [
+              { "k": "var", "name": "a" },
+              { "k": "var", "name": "a" }
+            ],
+            "retType": { "k": "con", "name": "Ordering" },
+            "body": {
+              "t": "ctor",
+              "type": "Ordering",
+              "ctor": "EQ",
+              "args": []
+            }
+          }
+        }
+      ]
+    },
+    {
+      "kind": "instance",
+      "class": "Ord",
+      "type": { "k": "con", "name": "Bool" },
+      "doc": "Ord Bool. Body lowered via `try_emit_primitive_instance_body::\"compare__Bool\"` — `icmp ult i1` LT-test, `icmp eq i1` EQ-test, GT default.",
+      "methods": [
+        {
+          "name": "compare",
+          "body": {
+            "t": "lam",
+            "params": ["x", "y"],
+            "paramTypes": [
+              { "k": "var", "name": "a" },
+              { "k": "var", "name": "a" }
+            ],
+            "retType": { "k": "con", "name": "Ordering" },
+            "body": {
+              "t": "ctor",
+              "type": "Ordering",
+              "ctor": "EQ",
+              "args": []
+            }
+          }
+        }
+      ]
+    },
+    {
+      "kind": "instance",
+      "class": "Ord",
+      "type": { "k": "con", "name": "Str" },
+      "doc": "Ord Str. Body lowered via `try_emit_primitive_instance_body::\"compare__Str\"` — `call i32 @ail_str_compare(ptr, ptr)` then branch on slt-0 / eq-0 against the normalised {-1, 0, +1} return.",
+      "methods": [
+        {
+          "name": "compare",
+          "body": {
+            "t": "lam",
+            "params": ["x", "y"],
+            "paramTypes": [
+              { "k": "var", "name": "a" },
+              { "k": "var", "name": "a" }
+            ],
+            "retType": { "k": "con", "name": "Ordering" },
+            "body": {
+              "t": "ctor",
+              "type": "Ordering",
+              "ctor": "EQ",
+              "args": []
+            }
+          }
+        }
+      ]
     }
   ]
 }