diff --git a/google/genai/_extra_utils.py b/google/genai/_extra_utils.py
index e0fb9c105..be1853bd3 100644
--- a/google/genai/_extra_utils.py
+++ b/google/genai/_extra_utils.py
@@ -437,6 +437,15 @@ def should_disable_afc(
     )
     return True
 
+  # If there are no tools, disable AFC.
+  if not config_model.tools:
+    if config_model.automatic_function_calling:
+      logger.warning(
+          'No tools are specified in the config, but automatic_function_calling'
+          ' is enabled. Therefore, automatic function calling is disabled.'
+      )
+    return True
+
   # Default to enable AFC if not specified.
   if (
       not config_model.automatic_function_calling
diff --git a/google/genai/tests/afc/test_get_max_remote_calls_for_afc.py b/google/genai/tests/afc/test_get_max_remote_calls_for_afc.py
index 5a72020ed..52d5038c4 100644
--- a/google/genai/tests/afc/test_get_max_remote_calls_for_afc.py
+++ b/google/genai/tests/afc/test_get_max_remote_calls_for_afc.py
@@ -26,7 +26,14 @@ def test_config_is_none():
 
 
 def test_afc_unset_max_unset():
-  assert get_max_remote_calls_afc(types.GenerateContentConfig()) == 10
+  assert (
+      get_max_remote_calls_afc(
+          types.GenerateContentConfig(
+              tools=[types.Tool(retrieval=types.Retrieval())]
+          )
+      )
+      == 10
+  )
 
 
 def test_afc_unset_max_set():
@@ -36,6 +43,7 @@ def test_afc_unset_max_set():
               automatic_function_calling=types.AutomaticFunctionCallingConfig(
                   maximum_remote_calls=20,
               ),
+              tools=[types.Tool(retrieval=types.Retrieval())],
           )
       )
       == 20
@@ -72,6 +80,7 @@ def test_afc_d_max_unset():
               automatic_function_calling=types.AutomaticFunctionCallingConfig(
                   disable=False,
               ),
+              tools=[types.Tool(retrieval=types.Retrieval())],
           )
       )
       == 10
@@ -86,6 +95,7 @@ def test_afc_d_max_set():
                   disable=False,
                   maximum_remote_calls=5,
               ),
+              tools=[types.Tool(retrieval=types.Retrieval())],
           )
       )
       == 5
@@ -96,10 +106,11 @@ def test_afc_enabled_max_set_to_zero():
   with pytest.raises(ValueError):
     get_max_remote_calls_afc(
         types.GenerateContentConfig(
-          automatic_function_calling=types.AutomaticFunctionCallingConfig(
+            automatic_function_calling=types.AutomaticFunctionCallingConfig(
                 disable=False,
                 maximum_remote_calls=0,
             ),
+            tools=[types.Tool(retrieval=types.Retrieval())],
         )
     )
 
@@ -124,6 +135,7 @@ def test_afc_enabled_max_set_to_float():
                   disable=False,
                   maximum_remote_calls=5.0,
               ),
+              tools=[types.Tool(retrieval=types.Retrieval())],
           )
       )
       == 5
diff --git a/google/genai/tests/afc/test_should_disable_afc.py b/google/genai/tests/afc/test_should_disable_afc.py
index 188bf2b57..89bc03f22 100644
--- a/google/genai/tests/afc/test_should_disable_afc.py
+++ b/google/genai/tests/afc/test_should_disable_afc.py
@@ -26,7 +26,41 @@ def test_config_is_none():
 
 
 def test_afc_config_unset():
-  assert should_disable_afc(types.GenerateContentConfig()) is False
+  assert should_disable_afc(types.GenerateContentConfig()) is True
+
+
+def test_afc_config_with_tools():
+  assert (
+      should_disable_afc(
+          types.GenerateContentConfig(
+              tools=[types.Tool(retrieval=types.Retrieval())]
+          )
+      )
+      is False
+  )
+
+
+def test_afc_config_with_empty_tools_when_afc_is_enabled():
+  assert (
+      should_disable_afc(
+          types.GenerateContentConfig(
+              automatic_function_calling=types.AutomaticFunctionCallingConfig(),
+              tools=[],
+          )
+      )
+      is True
+  )
+
+
+def test_afc_config_without_tools_when_afc_is_enabled():
+  assert (
+      should_disable_afc(
+          types.GenerateContentConfig(
+              automatic_function_calling=types.AutomaticFunctionCallingConfig()
+          )
+      )
+      is True
+  )
 
 
 def test_afc_enable_unset_max_0():
@@ -71,6 +105,7 @@ def test_afc_enable_unset_max_1():
               automatic_function_calling=types.AutomaticFunctionCallingConfig(
                   maximum_remote_calls=1,
               ),
+              tools=[types.Tool(retrieval=types.Retrieval())],
           )
       )
       is False
@@ -80,9 +115,11 @@ def test_afc_enable_unset_max_1():
 def test_afc_enable_unset_max_1_0():
   assert (
       should_disable_afc(
-          {'automatic_function_calling': {'maximum_remote_calls': 1.0}}
+          {
+              'automatic_function_calling': {'maximum_remote_calls': 1.0},
+          }
       )
-      is False
+      is True
   )
 
 
@@ -157,6 +194,7 @@ def test_afc_enable_true_max_unset():
               automatic_function_calling=types.AutomaticFunctionCallingConfig(
                   disable=False,
               ),
+              tools=[types.Tool(retrieval=types.Retrieval())],
           )
       )
       is False
@@ -208,6 +246,7 @@ def test_afc_enable_true_max_1():
                   disable=False,
                   maximum_remote_calls=1,
               ),
+              tools=[types.Tool(retrieval=types.Retrieval())],
           )
       )
       is False