diff --git a/src/google/adk/cli/fast_api.py b/src/google/adk/cli/fast_api.py
index 086d433..f898362 100644
--- a/src/google/adk/cli/fast_api.py
+++ b/src/google/adk/cli/fast_api.py
@@ -76,6 +76,7 @@ from .cli_eval import EvalMetric
 from .cli_eval import EvalMetricResult
 from .cli_eval import EvalSetResult
 from .cli_eval import EvalStatus
+from .utils import common
 from .utils import create_empty_state
 from .utils import envs
 from .utils import evals
@@ -119,27 +120,18 @@ class AgentRunRequest(BaseModel):
   streaming: bool = False
 
 
-class AddSessionToEvalSetRequest(BaseModel):
+class AddSessionToEvalSetRequest(common.BaseModel):
   eval_id: str
   session_id: str
   user_id: str
 
 
-class RunEvalRequest(BaseModel):
-  model_config = ConfigDict(
-      alias_generator=alias_generators.to_camel,
-  )
-
+class RunEvalRequest(common.BaseModel):
   eval_ids: list[str]  # if empty, then all evals in the eval set are run.
   eval_metrics: list[EvalMetric]
 
 
-class RunEvalResult(BaseModel):
-  model_config = ConfigDict(
-      alias_generator=alias_generators.to_camel,
-      populate_by_name=True,
-  )
-
+class RunEvalResult(common.BaseModel):
   eval_set_file: str
   eval_set_id: str
   eval_id: str
diff --git a/src/google/adk/cli/utils/common.py b/src/google/adk/cli/utils/common.py
new file mode 100644
index 0000000..522fdef
--- /dev/null
+++ b/src/google/adk/cli/utils/common.py
@@ -0,0 +1,23 @@
+# Copyright 2025 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import pydantic
+from pydantic import alias_generators
+
+
+class BaseModel(pydantic.BaseModel):
+  model_config = pydantic.ConfigDict(
+      alias_generator=alias_generators.to_camel,
+      populate_by_name=True,
+  )