diff --git a/azure/durable_functions/models/TokenSource.py b/azure/durable_functions/models/TokenSource.py
index d6ced05f..36b3c5f8 100644
--- a/azure/durable_functions/models/TokenSource.py
+++ b/azure/durable_functions/models/TokenSource.py
@@ -32,6 +32,7 @@ class ManagedIdentityTokenSource(TokenSource):
     def __init__(self, resource: str):
         super().__init__()
         self._resource: str = resource
+        self._kind: str = "AzureManagedIdentity"
 
     @property
     def resource(self) -> str:
@@ -51,4 +52,5 @@ def to_json(self) -> Dict[str, Union[str, int]]:
         """
         json_dict: Dict[str, Union[str, int]] = {}
         add_attrib(json_dict, self, 'resource')
+        json_dict["kind"] = self._kind
         return json_dict
diff --git a/tests/models/test_TokenSource.py b/tests/models/test_TokenSource.py
new file mode 100644
index 00000000..30dfe28f
--- /dev/null
+++ b/tests/models/test_TokenSource.py
@@ -0,0 +1,11 @@
+from azure.durable_functions.models.TokenSource import ManagedIdentityTokenSource
+
+def test_serialization_fields():
+    """Validates the TokenSource contains the expected fields when serialized to JSON"""
+    token_source = ManagedIdentityTokenSource(resource="TOKEN_SOURCE")
+    token_source_json = token_source.to_json()
+
+    # Output JSON should contain a resource field and a kind field set to `AzureManagedIdentity`
+    assert "resource" in token_source_json.keys()
+    assert "kind" in token_source_json.keys()
+    assert token_source_json["kind"] == "AzureManagedIdentity"
\ No newline at end of file