refactor(google_gemini.py): simplify system prompt handling and update documentation

Author: owndev

docs/google-gemini-integration.md

@@ -251,72 +251,48 @@ To use this filter, ensure it's enabled in your Open WebUI configuration. Then,
 
 Native tool calling is enabled/disabled via the standard 'Function calling' Open Web UI toggle.
 
-## System Prompt Hierarchy
+## Default System Prompt
 
-The Google Gemini pipeline supports a hierarchical system prompt configuration that combines multiple sources. This allows for flexible customization at different levels: global defaults and user preferences.
-
-### Prompt Sources (in order of combination)
-
-1. **Default System Prompt** (`GOOGLE_DEFAULT_SYSTEM_PROMPT`): Global default applied to all chats, configurable via environment variable or Admin UI valves.
-
-2. **User System Prompt**: The user's personalized system prompt from either:
-   - **Chat Controls**: The system message passed with individual chat messages
-   - **User Settings** (Settings > Personalization): Stored in `settings.ui.system`
-   
-   Note: Chat controls take precedence over user settings if both are set.
+The Google Gemini pipeline supports a configurable default system prompt that is applied to all chats. This is useful when you want to consistently apply certain behaviors or instructions to all Gemini models without having to configure each model individually.
 
 ### How It Works
 
-All available prompts are combined in order, separated by blank lines:
-
-```
-{Default System Prompt}
-
-{User System Prompt}
-```
-
-If only one prompt source is set, it is used as-is without any additional formatting.
+- **Default Only**: If only `GOOGLE_DEFAULT_SYSTEM_PROMPT` is set and no user-defined system prompt exists, the default prompt is used as the system instruction.
+- **User Only**: If only a user-defined system prompt exists (from model settings), it is used as-is.
+- **Both**: If both are set, the default system prompt is **prepended** to the user-defined prompt, separated by a blank line. This allows you to have base instructions that apply to all chats while still allowing model-specific customization.
 
 ### Configuration
 
-**Environment Variable:**
+Set via environment variable:
 
 ```bash
 # Default system prompt applied to all chats
-# Combined with user prompts if they exist
+# If a user-defined system prompt exists, this is prepended to it
 GOOGLE_DEFAULT_SYSTEM_PROMPT="You are a helpful AI assistant. Always be concise and accurate."
 ```
 
 Or configure through the pipeline valves in Open WebUI's Admin panel.
 
-**User System Prompt:**
-
-Users can set their personalized system prompt in Open WebUI:
-1. Go to Settings > Personalization
-2. Enter your preferred system prompt in the "System Prompt" field
-3. Save settings
-
-Alternatively, users can override the system prompt per-chat using chat controls. If both are set, the chat controls value takes precedence.
-
 ### Example
 
-If your configuration is:
+If your default system prompt is:
 
-**Default system prompt (`GOOGLE_DEFAULT_SYSTEM_PROMPT`):**
 ```
 You are a helpful AI assistant.
 ```
 
-**User system prompt (chat controls OR Settings > Personalization):**
+And your model-specific system prompt is:
+
 ```
-My name is John. I prefer detailed explanations.
+Always respond in formal English.
 ```
 
 The combined system prompt sent to Gemini will be:
+
 ```
 You are a helpful AI assistant.
 
-My name is John. I prefer detailed explanations.
+Always respond in formal English.
 ```
 
 ## Thinking Configuration
@@ -438,9 +414,9 @@ print(response.text)
 
 ### Model Compatibility
 
-| Model | thinking_level | thinking_budget |
-|-------|---------------|-----------------|
-| gemini-3-* | ✅ Supported ("low", "high") | ❌ Not used |
-| gemini-2.5-* | ❌ Not used | ✅ Supported (0-32768) |
-| gemini-2.5-flash-image-* | ❌ Not supported | ❌ Not supported |
-| Other models | ❌ Not used | ✅ May be supported |
+| Model                     | thinking_level               | thinking_budget        |
+| ------------------------- | ---------------------------- | ---------------------- |
+| gemini-3-\*               | ✅ Supported ("low", "high") | ❌ Not used            |
+| gemini-2.5-\*             | ❌ Not used                  | ✅ Supported (0-32768) |
+| gemini-2.5-flash-image-\* | ❌ Not supported             | ❌ Not supported       |
+| Other models              | ❌ Not used                  | ✅ May be supported    |

pipelines/google/google_gemini.py

@@ -34,7 +34,6 @@
   - Flexible upload fallback options and optimization controls
   - Configurable thinking levels (low/high) for Gemini 3 models
   - Configurable thinking budgets (0-32768 tokens) for Gemini 2.5 models
-  - Hierarchical system prompts (default, user)
 """
 
 import os
@@ -209,8 +208,8 @@ class Valves(BaseModel):
         )
         DEFAULT_SYSTEM_PROMPT: str = Field(
             default=os.getenv("GOOGLE_DEFAULT_SYSTEM_PROMPT", ""),
-            description="Default system prompt applied to all chats. Combined with user prompt "
-            "in a hierarchy: default → user. Leave empty to disable.",
+            description="Default system prompt applied to all chats. If a user-defined system prompt exists, "
+            "this is prepended to it. Leave empty to disable.",
         )
 
         # Image Processing Configuration
@@ -291,78 +290,38 @@ def _deduplicate_images(self, images: List[Dict[str, Any]]) -> List[Dict[str, An
             result.append(part)
         return result
 
-    def _get_user_personalization_prompt(
-        self, __user__: Optional[dict] = None
-    ) -> Optional[str]:
-        """Get the per-user system prompt from user settings (Personalization).
-
-        In Open WebUI, users can configure a personalized system prompt
-        in Settings > Personalization. This is stored in __user__["settings"]["ui"]["system"].
-
-        Args:
-            __user__: The user dict passed to the pipe method
-
-        Returns:
-            The user's personalized system prompt or None if not set
-        """
-        if __user__ is None:
-            return None
-
-        try:
-            settings = __user__.get("settings")
-            if settings and isinstance(settings, dict):
-                ui_settings = settings.get("ui")
-                if ui_settings and isinstance(ui_settings, dict):
-                    system_prompt = ui_settings.get("system")
-                    if system_prompt and isinstance(system_prompt, str):
-                        return system_prompt.strip() or None
-        except Exception as e:
-            self.log.debug(f"Could not retrieve user personalization prompt: {e}")
-
-        return None
-
     def _combine_system_prompts(
-        self,
-        chat_system_prompt: Optional[str],
-        __user__: Optional[dict] = None,
+        self, user_system_prompt: Optional[str]
     ) -> Optional[str]:
-        """Combine default and user system prompts.
+        """Combine default system prompt with user-defined system prompt.
 
-        Prompt hierarchy (all prompts are combined if set):
-        1. DEFAULT_SYSTEM_PROMPT (environment/valve setting)
-        2. User system prompt (from chat controls OR user settings - chat controls take precedence)
+        If DEFAULT_SYSTEM_PROMPT is set and user_system_prompt exists,
+        the default is prepended to the user's prompt.
+        If only DEFAULT_SYSTEM_PROMPT is set, it is used as the system prompt.
+        If only user_system_prompt is set, it is used as-is.
 
         Args:
-            chat_system_prompt: The chat-level system prompt from messages (may be None)
-            __user__: The user dict passed to the pipe method
+            user_system_prompt: The user-defined system prompt from messages (may be None)
 
         Returns:
-            Combined system prompt or None if none are set
+            Combined system prompt or None if neither is set
         """
-        default_prompt = self.valves.DEFAULT_SYSTEM_PROMPT.strip() or None
-        user_personalization = self._get_user_personalization_prompt(__user__)
-        chat_prompt = chat_system_prompt.strip() if chat_system_prompt else None
+        default_prompt = self.valves.DEFAULT_SYSTEM_PROMPT.strip()
+        user_prompt = user_system_prompt.strip() if user_system_prompt else ""
 
-        # User prompt = chat controls OR user settings (chat controls take precedence if both are set)
-        user_prompt = chat_prompt or user_personalization
-
-        prompts = [p for p in [default_prompt, user_prompt] if p]
-
-        if not prompts:
-            return None
-
-        if len(prompts) == 1:
-            self.log.debug(f"Using single system prompt ({len(prompts[0])} chars)")
-            return prompts[0]
-
-        combined = "\n\n".join(prompts)
-        self.log.debug(
-            f"Combined system prompts: "
-            f"default={len(default_prompt) if default_prompt else 0}, "
-            f"user={len(user_prompt) if user_prompt else 0} -> "
-            f"total={len(combined)} chars"
-        )
-        return combined
+        if default_prompt and user_prompt:
+            combined = f"{default_prompt}\n\n{user_prompt}"
+            self.log.debug(
+                f"Combined system prompts: default ({len(default_prompt)} chars) + "
+                f"user ({len(user_prompt)} chars) = {len(combined)} chars"
+            )
+            return combined
+        elif default_prompt:
+            self.log.debug(f"Using default system prompt ({len(default_prompt)} chars)")
+            return default_prompt
+        elif user_prompt:
+            return user_prompt
+        return None
 
     def _apply_order_and_limit(
         self,
@@ -449,7 +408,6 @@ async def _build_image_generation_contents(
         self,
         messages: List[Dict[str, Any]],
         __event_emitter__: Callable,
-        __user__: Optional[dict] = None,
     ) -> Tuple[List[Dict[str, Any]], Optional[str]]:
         """Construct the contents payload for image-capable models.
 
@@ -462,9 +420,7 @@ async def _build_image_generation_contents(
         )
 
         # Combine with default system prompt if configured
-        system_instruction = self._combine_system_prompts(
-            user_system_instruction, __user__
-        )
+        system_instruction = self._combine_system_prompts(user_system_instruction)
 
         last_user_msg = next(
             (m for m in reversed(messages) if m.get("role") == "user"), None
@@ -923,16 +879,13 @@ def _prepare_model_id(self, model_id: str) -> str:
         return model_id
 
     def _prepare_content(
-        self,
-        messages: List[Dict[str, Any]],
-        __user__: Optional[dict] = None,
+        self, messages: List[Dict[str, Any]]
     ) -> Tuple[List[Dict[str, Any]], Optional[str]]:
         """
         Prepare messages content for the API and extract system message if present.
 
         Args:
             messages: List of message objects from the request
-            __user__: The user dict passed to the pipe method
 
         Returns:
             Tuple of (prepared content list, system message string or None)
@@ -944,7 +897,7 @@ def _prepare_content(
         )
 
         # Combine with default system prompt if configured
-        system_message = self._combine_system_prompts(user_system_message, __user__)
+        system_message = self._combine_system_prompts(user_system_message)
 
         # Prepare contents for the API
         contents = []
@@ -2203,7 +2156,7 @@ async def pipe(
                         contents,
                         system_instruction,
                     ) = await self._build_image_generation_contents(
-                        messages, __event_emitter__, __user__
+                        messages, __event_emitter__
                     )
                     # For image generation, system_instruction is integrated into the prompt
                     # so it will be None here (this is expected and correct)
@@ -2215,7 +2168,7 @@ async def pipe(
             else:
                 # For non-image generation models, use the full conversation history
                 # Prepare content and extract system message normally
-                contents, system_instruction = self._prepare_content(messages, __user__)
+                contents, system_instruction = self._prepare_content(messages)
                 if not contents:
                     return "Error: No valid message content found"
                 self.log.debug(