diff --git a/src/google/adk/cli/cli_tools_click.py b/src/google/adk/cli/cli_tools_click.py
index 1bee5355..b841e017 100644
--- a/src/google/adk/cli/cli_tools_click.py
+++ b/src/google/adk/cli/cli_tools_click.py
@@ -754,10 +754,8 @@ def cli_create_eval_set(
     type=click.Path(
         exists=True, dir_okay=False, file_okay=True, resolve_path=True
     ),
-    help=(
-        "Optional. Path to session file containing SessionInput in JSON format."
-    ),
-    default=None,
+    help="Path to session file containing SessionInput in JSON format.",
+    required=True,
 )
 @eval_options()
 def cli_add_eval_case(
@@ -787,10 +785,8 @@ def cli_add_eval_case(
   eval_sets_manager = get_eval_sets_manager(eval_storage_uri, agents_dir)
 
   try:
-    session_input = None
-    if session_input_file:
-      with open(session_input_file, "r") as f:
-        session_input = SessionInput.model_validate_json(f.read())
+    with open(session_input_file, "r") as f:
+      session_input = SessionInput.model_validate_json(f.read())
 
     with open(scenarios_file, "r") as f:
       conversation_scenarios = ConversationScenarios.model_validate_json(
diff --git a/tests/unittests/cli/utils/test_cli_tools_click.py b/tests/unittests/cli/utils/test_cli_tools_click.py
index 3bd02b39..be9015ca 100644
--- a/tests/unittests/cli/utils/test_cli_tools_click.py
+++ b/tests/unittests/cli/utils/test_cli_tools_click.py
@@ -643,50 +643,6 @@ def test_cli_create_eval_set(tmp_path: Path):
   assert eval_set_data["eval_cases"] == []
 
 
-def test_cli_add_eval_case_no_session(tmp_path: Path):
-  app_name = "test_app_add_1"
-  eval_set_id = "test_eval_set_add_1"
-  agent_path = tmp_path / app_name
-  agent_path.mkdir()
-  (agent_path / "__init__.py").touch()
-
-  scenarios_file = tmp_path / "scenarios1.json"
-  scenarios_file.write_text(
-      '{"scenarios": [{"starting_prompt": "hello", "conversation_plan":'
-      ' "world"}]}'
-  )
-
-  runner = CliRunner()
-  runner.invoke(
-      cli_tools_click.main,
-      ["eval_set", "create", str(agent_path), eval_set_id],
-      catch_exceptions=False,
-  )
-  result = runner.invoke(
-      cli_tools_click.main,
-      [
-          "eval_set",
-          "add_eval_case",
-          str(agent_path),
-          eval_set_id,
-          "--scenarios_file",
-          str(scenarios_file),
-      ],
-      catch_exceptions=False,
-  )
-
-  assert result.exit_code == 0
-  eval_set_file = agent_path / f"{eval_set_id}.evalset.json"
-  assert eval_set_file.exists()
-  with open(eval_set_file, "r") as f:
-    eval_set_data = json.load(f)
-  assert len(eval_set_data["eval_cases"]) == 1
-  eval_case = eval_set_data["eval_cases"][0]
-  assert eval_case["eval_id"] == "0a1a5048"
-  assert eval_case["conversation_scenario"]["starting_prompt"] == "hello"
-  assert "session_input" not in eval_case
-
-
 def test_cli_add_eval_case_with_session(tmp_path: Path):
   app_name = "test_app_add_2"
   eval_set_id = "test_eval_set_add_2"
@@ -748,6 +704,10 @@ def test_cli_add_eval_case_skip_existing(tmp_path: Path):
       '{"scenarios": [{"starting_prompt": "hello", "conversation_plan":'
       ' "world"}]}'
   )
+  session_file = tmp_path / "session3.json"
+  session_file.write_text(
+      '{"app_name": "test_app_add_3", "user_id": "test_user", "state": {}}'
+  )
 
   runner = CliRunner()
   runner.invoke(
@@ -764,6 +724,8 @@ def test_cli_add_eval_case_skip_existing(tmp_path: Path):
           eval_set_id,
           "--scenarios_file",
           str(scenarios_file),
+          "--session_input_file",
+          str(session_file),
       ],
       catch_exceptions=False,
   )
@@ -780,6 +742,8 @@ def test_cli_add_eval_case_skip_existing(tmp_path: Path):
           eval_set_id,
           "--scenarios_file",
           str(scenarios_file),
+          "--session_input_file",
+          str(session_file),
       ],
       catch_exceptions=False,
   )