Address code review feedback: improve type hints, validation, and documentation

Co-authored-by: hlohaus <983577+hlohaus@users.noreply.github.com>

g4f/mcp/tools.py

@@ -29,8 +29,15 @@ class MCPTool(ABC):
         pass
     
     @abstractmethod
-    async def execute(self, arguments: Dict[str, Any]) -> Any:
-        """Execute the tool with given arguments"""
+    async def execute(self, arguments: Dict[str, Any]) -> Dict[str, Any]:
+        """Execute the tool with given arguments
+        
+        Args:
+            arguments: Tool input arguments matching the input_schema
+            
+        Returns:
+            Dict containing either results or an error key with error message
+        """
         pass
 
 
@@ -60,7 +67,11 @@ class WebSearchTool(MCPTool):
         }
     
     async def execute(self, arguments: Dict[str, Any]) -> Dict[str, Any]:
-        """Execute web search"""
+        """Execute web search
+        
+        Returns:
+            Dict[str, Any]: Search results or error message
+        """
         from ..tools.web_search import do_search
         
         query = arguments.get("query", "")
@@ -72,7 +83,8 @@ class WebSearchTool(MCPTool):
             }
         
         try:
-            # Perform search
+            # Perform search - query parameter is used for search execution
+            # and prompt parameter holds the content to be searched
             result, sources = await do_search(
                 prompt=query,
                 query=query,
@@ -127,7 +139,11 @@ class WebScrapeTool(MCPTool):
         }
     
     async def execute(self, arguments: Dict[str, Any]) -> Dict[str, Any]:
-        """Execute web scraping"""
+        """Execute web scraping
+        
+        Returns:
+            Dict[str, Any]: Scraped content or error message
+        """
         from ..tools.fetch_and_scrape import fetch_and_scrape
         from aiohttp import ClientSession
         
@@ -202,7 +218,11 @@ class ImageGenerationTool(MCPTool):
         }
     
     async def execute(self, arguments: Dict[str, Any]) -> Dict[str, Any]:
-        """Execute image generation"""
+        """Execute image generation
+        
+        Returns:
+            Dict[str, Any]: Generated image data or error message
+        """
         from ..client import AsyncClient
         from ..image import to_data_uri
         import base64
@@ -228,35 +248,49 @@ class ImageGenerationTool(MCPTool):
                 height=height
             )
             
-            # Get the image data
-            if response and hasattr(response, 'data') and response.data:
-                image_data = response.data[0]
-                
-                # Convert to base64 if needed
-                if hasattr(image_data, 'url'):
-                    image_url = image_data.url
-                    
-                    # Check if it's already a data URI
-                    if image_url.startswith('data:'):
-                        return {
-                            "prompt": prompt,
-                            "model": model,
-                            "width": width,
-                            "height": height,
-                            "image": image_url
-                        }
-                    else:
-                        return {
-                            "prompt": prompt,
-                            "model": model,
-                            "width": width,
-                            "height": height,
-                            "image_url": image_url
-                        }
+            # Get the image data with proper validation
+            if not response:
+                return {
+                    "error": "Image generation failed: No response from provider"
+                }
             
-            return {
-                "error": "Image generation failed: No image data in response"
-            }
+            if not hasattr(response, 'data') or not response.data:
+                return {
+                    "error": "Image generation failed: No image data in response"
+                }
+            
+            if len(response.data) == 0:
+                return {
+                    "error": "Image generation failed: Empty image data array"
+                }
+            
+            image_data = response.data[0]
+            
+            # Check if image_data has url attribute
+            if not hasattr(image_data, 'url'):
+                return {
+                    "error": "Image generation failed: No URL in image data"
+                }
+            
+            image_url = image_data.url
+            
+            # Return result based on URL type
+            if image_url.startswith('data:'):
+                return {
+                    "prompt": prompt,
+                    "model": model,
+                    "width": width,
+                    "height": height,
+                    "image": image_url
+                }
+            else:
+                return {
+                    "prompt": prompt,
+                    "model": model,
+                    "width": width,
+                    "height": height,
+                    "image_url": image_url
+                }
         
         except Exception as e:
             return {