fix(gemini): normalize ai studio google search tools

backend/internal/service/gemini_messages_compat_service.go

@@ -612,7 +612,8 @@ func (s *GeminiMessagesCompatService) Forward(ctx context.Context, c *gin.Contex
 				fullURL += "?alt=sse"
 			}
 
-			upstreamReq, err := http.NewRequestWithContext(ctx, http.MethodPost, fullURL, bytes.NewReader(geminiReq))
+			restGeminiReq := normalizeGeminiRequestForAIStudio(geminiReq)
+			upstreamReq, err := http.NewRequestWithContext(ctx, http.MethodPost, fullURL, bytes.NewReader(restGeminiReq))
 			if err != nil {
 				return nil, "", err
 			}
@@ -685,7 +686,8 @@ func (s *GeminiMessagesCompatService) Forward(ctx context.Context, c *gin.Contex
 					fullURL += "?alt=sse"
 				}
 
-				upstreamReq, err := http.NewRequestWithContext(ctx, http.MethodPost, fullURL, bytes.NewReader(geminiReq))
+				restGeminiReq := normalizeGeminiRequestForAIStudio(geminiReq)
+				upstreamReq, err := http.NewRequestWithContext(ctx, http.MethodPost, fullURL, bytes.NewReader(restGeminiReq))
 				if err != nil {
 					return nil, "", err
 				}
@@ -3240,6 +3242,46 @@ func convertClaudeToolsToGeminiTools(tools any) []any {
 	return out
 }
 
+func normalizeGeminiRequestForAIStudio(body []byte) []byte {
+	var payload map[string]any
+	if err := json.Unmarshal(body, &payload); err != nil {
+		return body
+	}
+
+	tools, ok := payload["tools"].([]any)
+	if !ok || len(tools) == 0 {
+		return body
+	}
+
+	modified := false
+	for _, rawTool := range tools {
+		tool, ok := rawTool.(map[string]any)
+		if !ok {
+			continue
+		}
+		googleSearch, ok := tool["googleSearch"]
+		if !ok {
+			continue
+		}
+		if _, exists := tool["google_search"]; exists {
+			continue
+		}
+		tool["google_search"] = googleSearch
+		delete(tool, "googleSearch")
+		modified = true
+	}
+
+	if !modified {
+		return body
+	}
+
+	normalized, err := json.Marshal(payload)
+	if err != nil {
+		return body
+	}
+	return normalized
+}
+
 func isClaudeWebSearchToolMap(tool map[string]any) bool {
 	toolType, _ := tool["type"].(string)
 	if strings.HasPrefix(toolType, "web_search") || toolType == "google_search" {