Support gemini-3-pro-image-preview with Nano Banana Pro (#3576)

Author: DouweM

docs/builtin-tools.md

@@ -202,7 +202,7 @@ The [`ImageGenerationTool`][pydantic_ai.builtin_tools.ImageGenerationTool] enabl
 | Provider | Supported | Notes |
 |----------|-----------|-------|
 | OpenAI Responses | ✅ | Full feature support. Only supported by models newer than `gpt-5`. Metadata about the generated image, like the [`revised_prompt`](https://platform.openai.com/docs/guides/tools-image-generation#revised-prompt) sent to the underlying image model, is available on the [`BuiltinToolReturnPart`][pydantic_ai.messages.BuiltinToolReturnPart] that's available via [`ModelResponse.builtin_tool_calls`][pydantic_ai.messages.ModelResponse.builtin_tool_calls]. |
-| Google | ✅ | No parameter support. Only supported by [image generation models](https://ai.google.dev/gemini-api/docs/image-generation) like `gemini-2.5-flash-image`. These models do not support [structured output](output.md) or [function tools](tools.md). These models will always generate images, even if this built-in tool is not explicitly specified. |
+| Google | ✅ | No parameter support. Only supported by [image generation models](https://ai.google.dev/gemini-api/docs/image-generation) like `gemini-2.5-flash-image` and `gemini-3-pro-image-preview`. These models do not support [function tools](tools.md). These models will always have the option of generating images, even if this built-in tool is not explicitly specified. |
 | Anthropic | ❌ | |
 | Groq | ❌ | |
 | Bedrock | ❌ | |

pydantic_ai_slim/pydantic_ai/models/__init__.py

@@ -156,6 +156,7 @@
         'google-gla:gemini-2.5-flash-lite-preview-09-2025',
         'google-gla:gemini-2.5-pro',
         'google-gla:gemini-3-pro-preview',
+        'google-gla:gemini-3-pro-image-preview',
         'google-vertex:gemini-flash-latest',
         'google-vertex:gemini-flash-lite-latest',
         'google-vertex:gemini-2.0-flash',
@@ -167,6 +168,7 @@
         'google-vertex:gemini-2.5-flash-lite-preview-09-2025',
         'google-vertex:gemini-2.5-pro',
         'google-vertex:gemini-3-pro-preview',
+        'google-vertex:gemini-3-pro-image-preview',
         'grok:grok-2-image-1212',
         'grok:grok-2-vision-1212',
         'grok:grok-3',

pydantic_ai_slim/pydantic_ai/models/google.py

@@ -106,6 +106,7 @@
     'gemini-2.5-flash-lite-preview-09-2025',
     'gemini-2.5-pro',
     'gemini-3-pro-preview',
+    'gemini-3-pro-image-preview',
 ]
 """Latest Gemini models."""
 
@@ -420,7 +421,7 @@ async def _build_content_and_config(
         model_request_parameters: ModelRequestParameters,
     ) -> tuple[list[ContentUnionDict], GenerateContentConfigDict]:
         tools = self._get_tools(model_request_parameters)
-        if tools and not self.profile.supports_tools:
+        if model_request_parameters.function_tools and not self.profile.supports_tools:
             raise UserError('Tools are not supported by this model.')
 
         response_mime_type = None
@@ -559,7 +560,7 @@ async def _map_messages(
                         )
                     elif isinstance(part, RetryPromptPart):
                         if part.tool_name is None:
-                            message_parts.append({'text': part.model_response()})  # pragma: no cover
+                            message_parts.append({'text': part.model_response()})
                         else:
                             message_parts.append(
                                 {
@@ -741,6 +742,11 @@ async def _get_event_iterator(self) -> AsyncIterator[ModelResponseStreamEvent]:
                     if maybe_event is not None:  # pragma: no branch
                         yield maybe_event
                 elif part.inline_data is not None:
+                    if part.thought:  # pragma: no cover
+                        # Per https://ai.google.dev/gemini-api/docs/image-generation#thinking-process:
+                        # > The model generates up to two interim images to test composition and logic. The last image within Thinking is also the final rendered image.
+                        # We currently don't expose these image thoughts as they can't be represented with `ThinkingPart`
+                        continue
                     data = part.inline_data.data
                     mime_type = part.inline_data.mime_type
                     assert data and mime_type, 'Inline data must have data and mime type'

pydantic_ai_slim/pydantic_ai/profiles/google.py

@@ -25,8 +25,8 @@ def google_model_profile(model_name: str) -> ModelProfile | None:
     return GoogleModelProfile(
         json_schema_transformer=GoogleJsonSchemaTransformer,
         supports_image_output=is_image_model,
-        supports_json_schema_output=not is_image_model,
-        supports_json_object_output=not is_image_model,
+        supports_json_schema_output=is_3_or_newer or not is_image_model,
+        supports_json_object_output=is_3_or_newer or not is_image_model,
         supports_tools=not is_image_model,
         google_supports_native_output_with_builtin_tools=is_3_or_newer,
     )