diff --git a/Makefile b/Makefile
index dbc3b434..8ab0bab1 100644
--- a/Makefile
+++ b/Makefile
@@ -2,6 +2,8 @@
 
 default: test-all
 
+install: uv-sync
+
 uv-sync:
 	@uv sync --all-packages 2> /dev/null
 
diff --git a/packages/overture-schema-core/src/overture/schema/core/models.py b/packages/overture-schema-core/src/overture/schema/core/models.py
index 6460d26b..ed43eabe 100644
--- a/packages/overture-schema-core/src/overture/schema/core/models.py
+++ b/packages/overture-schema-core/src/overture/schema/core/models.py
@@ -12,7 +12,6 @@
 from pydantic_core import core_schema
 from typing_extensions import Self
 
-from overture.schema.core.sources import Sources
 from overture.schema.system.feature import Feature
 from overture.schema.system.field_constraint import UniqueItemsConstraint
 from overture.schema.system.model_constraint import no_extra_fields
@@ -25,6 +24,7 @@
 )
 
 from .enums import PerspectiveMode
+from .sources import Sources
 from .types import (
     FeatureVersion,
     Level,
@@ -66,7 +66,7 @@ def __validate_ext_fields__(self) -> Self:
             raise ValueError(
                 f"invalid extra field name{maybe_plural}: {', '.join(invalid_extra_fields)} "
                 "(extra fields are temporarily allowed, but only if their names start with 'ext_', "
-                "but all extra field name support in {self.__class__.name} is on a deprecation path "
+                "but all extra field name support in {self.__class__.__name__} is on a deprecation path"
                 "and will be removed)"
             )
         return self