diff --git a/adapters/python/adapter_template.py b/adapters/python/adapter_template.py
index cd206200..c14a2659 100644
--- a/adapters/python/adapter_template.py
+++ b/adapters/python/adapter_template.py
@@ -833,6 +833,23 @@ def _r2flutter_pool(strings: List[dict]) -> List[dict]:
     return out
 
 
+def _r2flutter_super_name(value) -> str:
+    """Normalize r2flutter superclass metadata to ProgramModel's string field."""
+    if isinstance(value, str):
+        name = value.strip()
+        if name:
+            return name
+    if isinstance(value, dict):
+        name = value.get("name")
+        if isinstance(name, str):
+            name = name.strip()
+            if name:
+                return name
+    # ProgramModel v3 requires a non-null superclass string. "Object" is only
+    # a placeholder for unresolved r2flutter metadata, not recovered data.
+    return "Object"
+
+
 def _r2flutter_classes(classes: List[dict]) -> List[dict]:
     """Project r2flutter classes onto ProgramModel classes.
 
@@ -849,7 +866,7 @@ def _r2flutter_classes(classes: List[dict]) -> List[dict]:
             {
                 "id": i,
                 "name": name,
-                "super": (c.get("super") or "Object"),
+                "super": _r2flutter_super_name(c.get("super")),
                 "lib": "",
             }
         )
diff --git a/crates/flutterdec-adapter/src/lib.rs b/crates/flutterdec-adapter/src/lib.rs
index 6b7d492b..ca5878ed 100644
--- a/crates/flutterdec-adapter/src/lib.rs
+++ b/crates/flutterdec-adapter/src/lib.rs
@@ -460,4 +460,104 @@ asm_dir.mkdir(parents=True, exist_ok=True)
             "generic onResume in non-activity owner should not be tagged as activity handler"
         );
     }
+
+    #[test]
+    fn run_adapter_r2flutter_backend_normalizes_structured_superclass() {
+        let td = tempdir().expect("tempdir");
+        let root = td.path();
+        let python_dir = root.join("python");
+        fs::create_dir_all(&python_dir).expect("mkdir python");
+
+        let repo_root = PathBuf::from(env!("CARGO_MANIFEST_DIR"))
+            .join("../..")
+            .canonicalize()
+            .expect("canonicalize repo root");
+        let template_src = repo_root.join("adapters/python/adapter_template.py");
+        fs::copy(&template_src, python_dir.join("adapter_template.py"))
+            .expect("copy adapter template");
+
+        let fake_r2flutter = root.join("fake_r2flutter");
+        fs::write(
+            &fake_r2flutter,
+            r#"#!/usr/bin/env python3
+import json
+import sys
+
+if "-jH" in sys.argv:
+    value = {
+        "dart_version": "3.6.2",
+        "hash": "testhash",
+    }
+elif "-ji" in sys.argv:
+    value = {
+        "entries": [
+            {
+                "index": 0,
+                "address": 4096,
+                "name": "method.Child.test",
+            }
+        ]
+    }
+elif "-jxz" in sys.argv:
+    value = []
+elif "-jc" in sys.argv:
+    value = [
+        {
+            "name": "Child",
+            "super": {"type_ref": 35836},
+        },
+        {
+            "name": "Widget",
+            "super": {"ref": 12, "name": "StatefulWidget"},
+        }
+    ]
+else:
+    raise SystemExit(1)
+
+print(json.dumps(value))
+"#,
+        )
+        .expect("write fake r2flutter");
+        let mut fake_perms = fs::metadata(&fake_r2flutter)
+            .expect("metadata")
+            .permissions();
+        fake_perms.set_mode(0o755);
+        fs::set_permissions(&fake_r2flutter, fake_perms).expect("chmod fake r2flutter");
+
+        let exec = root.join("adapter_exec.py");
+        fs::write(
+            &exec,
+            "#!/usr/bin/env python3\nfrom pathlib import Path\nimport os\nimport sys\nroot = Path(__file__).resolve().parent\nos.environ['FLUTTERDEC_R2FLUTTER_CMD'] = str(root / 'fake_r2flutter')\nsys.path.insert(0, str(root / 'python'))\nimport adapter_template\nif __name__ == '__main__':\n    raise SystemExit(adapter_template.entrypoint(default_snapshot_hash='testhash', default_version='unknown'))\n",
+        )
+        .expect("write exec");
+        let mut perms = fs::metadata(&exec).expect("metadata").permissions();
+        perms.set_mode(0o755);
+        fs::set_permissions(&exec, perms).expect("chmod exec");
+
+        let input_file = root.join("libapp.so");
+        fs::write(&input_file, b"dummy").expect("write dummy input");
+
+        let vm_data = vec![0u8; 64];
+        let iso_data = vec![0u8; 64];
+        let vm_instr = vec![0u8; 16];
+        let iso_instr = vec![0u8; 16];
+        let input = AdapterInput {
+            input_path: Some(&input_file),
+            libapp_path: None,
+            vm_data: &vm_data,
+            isolate_data: &iso_data,
+            vm_instr: &vm_instr,
+            isolate_instr: &iso_instr,
+            vm_instr_va: 0,
+            isolate_instr_va: 0,
+            backend: Some("r2flutter"),
+        };
+
+        let model = run_adapter(&exec, &input).expect("run adapter");
+        assert_eq!(model.classes.len(), 2);
+        assert_eq!(model.classes[0].name, "Child");
+        assert_eq!(model.classes[0].super_name, "Object");
+        assert_eq!(model.classes[1].name, "Widget");
+        assert_eq!(model.classes[1].super_name, "StatefulWidget");
+    }
 }