chore: log warning when user uses automatic function calling directly in Models or AsyncModels.

CHANGELOG.md

@@ -1,28 +1,5 @@
 # Changelog
 
-## [2.18.0](https://github.com/googleapis/python-genai/compare/v2.17.0...v2.18.0) (2026-08-12)
-
-
-### Features
-
-* Add interaction_status to LiveServerContent ([66e224c](https://github.com/googleapis/python-genai/commit/66e224c39c9527e0fef3a4f049ac33ec941e2f99))
-* **api:** Make the deferred service tier publicly available on Vertex ([e1f7c40](https://github.com/googleapis/python-genai/commit/e1f7c40f0a831f25ee71294fc8c195576d5fd126))
-* Enable json schema in FunctionDeclaration parser ([62d50d6](https://github.com/googleapis/python-genai/commit/62d50d6f172da5d6efa30838ab92da95b1327b5e))
-* Make speech_config a structured object. ([cc0d42e](https://github.com/googleapis/python-genai/commit/cc0d42e84583ed927b6c0dfae38da7f5f544b2da))
-* Support injecting httpx2 client. ([012804d](https://github.com/googleapis/python-genai/commit/012804d9b649a20da46a6041e37d126b9a0b79e0)), refs [#2680](https://github.com/googleapis/python-genai/issues/2680)
-
-
-### Bug Fixes
-
-* Improve AFC(automatic function calling) in chat including fixing bugs in AFC for generate_content_stream. also log warnings in generate_content, generate_content_stream and their async variants that AFC is meant to be used in chat experience, not directly in models module. ([fe6118e](https://github.com/googleapis/python-genai/commit/fe6118e3c7a9e83406bc722e34b7efca75f1ef13))
-
-
-### Performance Improvements
-
-* Build model validators on first use instead of at import ([66bfe95](https://github.com/googleapis/python-genai/commit/66bfe956f7a8b6c8d7c7eb949a9b6a499a4e2860)), refs [#2784](https://github.com/googleapis/python-genai/issues/2784)
-* Lazily import the interactions API to speed up import google.genai ([89dcfe5](https://github.com/googleapis/python-genai/commit/89dcfe5b28f5e794f9a5ac84e2d45e9e7b7bd803))
-* Stop importing the requests HTTP stack at module scope ([3a44936](https://github.com/googleapis/python-genai/commit/3a44936ea783363489967bd9d219fb26401585dd))
-
 ## [2.17.0](https://github.com/googleapis/python-genai/compare/v2.16.0...v2.17.0) (2026-08-06)
 
 

google/genai/models.py

@@ -6405,6 +6405,7 @@ def _generate_videos(
     return return_value
 
   _logged_generate_videos_deprecation_warning = False
+  _logged_afc_warning = False
 
   def embed_content(
       self,
@@ -6572,6 +6573,15 @@ def generate_content(
     logger.info(
         f'AFC is enabled with max remote calls: {remaining_remote_calls_afc}.'
     )
+    if not Models._logged_afc_warning:
+      logger.warning(
+          'Direct use of automatic function calling (AFC) in'
+          ' Models.generate_content is not recommended. Instead, we recommend'
+          ' to use AFC in Chat.send_message. Similarly, direct use of AFC in'
+          ' Models.generate_content_stream is not recommended. Instead, we'
+          ' recommend to use AFC in Chat.send_message_stream.'
+      )
+      Models._logged_afc_warning = True
     automatic_function_calling_history: list[types.Content] = []
     response = types.GenerateContentResponse()
     i = 0
@@ -6736,6 +6746,15 @@ def generate_content_stream(
     logger.info(
         f'AFC is enabled with max remote calls: {remaining_remote_calls_afc}.'
     )
+    if not Models._logged_afc_warning:
+      logger.warning(
+          'Direct use of automatic function calling (AFC) in '
+          'Models.generate_content_stream is not recommended. Instead, we '
+          'recommend to use AFC in Chat.send_message_stream. Similarly, direct '
+          'use of AFC in Models.generate_content is not recommended. Instead, '
+          'we recommend to use AFC in Chat.send_message.'
+      )
+      Models._logged_afc_warning = True
     automatic_function_calling_history: list[types.Content] = []
     i = 0
     while remaining_remote_calls_afc > 0:
@@ -8604,6 +8623,7 @@ async def _generate_videos(
     return return_value
 
   _logged_generate_videos_deprecation_warning = False
+  _logged_afc_warning = False
 
   async def generate_content(
       self,
@@ -8737,6 +8757,16 @@ async def generate_content(
       logger.info(
           f'AFC is enabled with max remote calls: {remaining_remote_calls_afc}.'
       )
+      if not AsyncModels._logged_afc_warning:
+        logger.warning(
+            'Direct use of automatic function calling (AFC) in '
+            'AsyncModels.generate_content is not recommended. Instead, we '
+            'recommend to use AFC in AsyncChat.send_message. Similarly, direct '
+            'use of AFC in AsyncModels.generate_content_stream is not '
+            'recommended. Instead, we recommend to use AFC in '
+            'AsyncChat.send_message_stream.'
+        )
+        AsyncModels._logged_afc_warning = True
       automatic_function_calling_history: list[types.Content] = []
       response = types.GenerateContentResponse()
 
@@ -8973,6 +9003,16 @@ async def stream_generator():  # type: ignore[no-untyped-def]
             'AFC is enabled with max remote calls:'
             f' {remaining_remote_calls_afc}.'
         )
+        if not AsyncModels._logged_afc_warning:
+          logger.warning(
+              'Direct use of automatic function calling (AFC) in '
+              'AsyncModels.generate_content_stream is not recommended. '
+              'Instead, we recommend to use AFC in '
+              'AsyncChat.send_message_stream. Similarly, direct use of AFC in '
+              'AsyncModels.generate_content is not recommended. '
+              'Instead, we recommend to use AFC in AsyncChat.send_message.'
+          )
+          AsyncModels._logged_afc_warning = True
         automatic_function_calling_history: list[types.Content] = []
         i = 0
         loop_contents = contents

google/genai/version.py

@@ -13,4 +13,4 @@
 # limitations under the License.
 #
 
-__version__ = '2.18.0' # x-release-please-version
+__version__ = '2.17.0' # x-release-please-version

pyproject.toml

@@ -3,7 +3,7 @@ requires = ["setuptools", "wheel", "twine>=6.1.0", "packaging>=24.2", "pkginfo>=
 
 [project]
 name = "google-genai"
-version = "2.18.0"
+version = "2.17.0"
 description = "GenAI Python SDK"
 readme = "README.md"
 license = "Apache-2.0"