feat: add A2ABaseModel

scripts/generate_types.sh

@@ -32,6 +32,7 @@ uv run datamodel-codegen \
   --use-one-literal-as-default \
   --class-name A2A \
   --use-standard-collections \
-  --use-subclass-enum
+  --use-subclass-enum \
+  --base-class a2a._base.A2ABaseModel
 
 echo "Codegen finished successfully."

src/a2a/_base.py

@@ -0,0 +1,13 @@
+from pydantic import BaseModel, ConfigDict
+
+
+class A2ABaseModel(BaseModel):
+    """Base class for shared behavior across A2A data models.
+
+    Provides a common configuration (e.g., alias-based population) and
+    serves as the foundation for future extensions or shared utilities.
+    """
+
+    model_config = ConfigDict(
+        populate_by_name=True,
+    )