diff --git a/pkgs/classgen/main.py b/pkgs/classgen/main.py
index 8cafe0b6c..c698c480a 100644
--- a/pkgs/classgen/main.py
+++ b/pkgs/classgen/main.py
@@ -165,14 +165,18 @@ def get_field_def(
     if not default and not default_factory and not field_meta:
         return f"{field_name}: {serialised_types}"
     field_init = "field("
-    if default:
-        field_init += f"default = {default}"
-    if default_factory:
-        field_init += f"default_factory = {default_factory}"
-    if field_meta:
-        field_init += f", metadata = {field_meta}"
 
-    return f"{field_name}: {serialised_types} = {field_init})"
+    init_args = []
+    if default:
+        init_args.append(f"default = {default}")
+    if default_factory:
+        init_args.append(f"default_factory = {default_factory}")
+    if field_meta:
+        init_args.append(f"metadata = {field_meta}")
+
+    field_init += ", ".join(init_args) + ")"
+
+    return f"{field_name}: {serialised_types} = {field_init}"
 
 
 # Recursive function to generate dataclasses from JSON schema
@@ -223,8 +227,11 @@ def generate_dataclass(schema: dict[str, Any], class_name: str = root_class) ->
                     known_classes.add(nested_class_name)
 
             elif inner_type and inner_type.get("type") != "object":
-                # Trivial type
-                field_types = map_json_type(inner_type)
+                # Trivial type:
+                # dict[str, inner_type]
+                field_types = {
+                    f"""dict[str, {" | ".join(map_json_type(inner_type))}]"""
+                }
 
             elif not inner_type:
                 # The type is a class