fix(gemini): preserve google search grounding tools

backend/internal/pkg/antigravity/request_transformer.go

@@ -730,24 +730,26 @@ func buildTools(tools []ClaudeTool) []GeminiToolDeclaration {
 		})
 	}
 
-	if len(funcDecls) == 0 {
-		if !hasWebSearch {
-			return nil
-		}
-
-		// Web Search 工具映射
-		return []GeminiToolDeclaration{{
+	var declarations []GeminiToolDeclaration
+	if len(funcDecls) > 0 {
+		declarations = append(declarations, GeminiToolDeclaration{
+			FunctionDeclarations: funcDecls,
+		})
+	}
+	if hasWebSearch {
+		declarations = append(declarations, GeminiToolDeclaration{
 			GoogleSearch: &GeminiGoogleSearch{
 				EnhancedContent: &GeminiEnhancedContent{
 					ImageSearch: &GeminiImageSearch{
 						MaxResultCount: 5,
 					},
 				},
 			},
-		}}
+		})
+	}
+	if len(declarations) == 0 {
+		return nil
 	}
 
-	return []GeminiToolDeclaration{{
-		FunctionDeclarations: funcDecls,
-	}}
+	return declarations
 }

backend/internal/pkg/antigravity/request_transformer_test.go

@@ -263,6 +263,29 @@ func TestBuildTools_CustomTypeTools(t *testing.T) {
 	}
 }
 
+func TestBuildTools_PreservesWebSearchAlongsideFunctions(t *testing.T) {
+	tools := []ClaudeTool{
+		{
+			Name:        "get_weather",
+			Description: "Get weather information",
+			InputSchema: map[string]any{"type": "object"},
+		},
+		{
+			Type: "web_search_20250305",
+			Name: "web_search",
+		},
+	}
+
+	result := buildTools(tools)
+	require.Len(t, result, 2)
+	require.Len(t, result[0].FunctionDeclarations, 1)
+	require.Equal(t, "get_weather", result[0].FunctionDeclarations[0].Name)
+	require.NotNil(t, result[1].GoogleSearch)
+	require.NotNil(t, result[1].GoogleSearch.EnhancedContent)
+	require.NotNil(t, result[1].GoogleSearch.EnhancedContent.ImageSearch)
+	require.Equal(t, 5, result[1].GoogleSearch.EnhancedContent.ImageSearch.MaxResultCount)
+}
+
 func TestBuildGenerationConfig_ThinkingDynamicBudget(t *testing.T) {
 	tests := []struct {
 		name        string
@@ -400,3 +423,36 @@ func TestTransformClaudeToGeminiWithOptions_PreservesBillingHeaderSystemBlock(t
 		})
 	}
 }
+
+func TestTransformClaudeToGeminiWithOptions_PreservesWebSearchAlongsideFunctions(t *testing.T) {
+	claudeReq := &ClaudeRequest{
+		Model: "claude-3-5-sonnet-latest",
+		Messages: []ClaudeMessage{
+			{
+				Role:    "user",
+				Content: json.RawMessage(`[{"type":"text","text":"hello"}]`),
+			},
+		},
+		Tools: []ClaudeTool{
+			{
+				Name:        "get_weather",
+				Description: "Get weather information",
+				InputSchema: map[string]any{"type": "object"},
+			},
+			{
+				Type: "web_search_20250305",
+				Name: "web_search",
+			},
+		},
+	}
+
+	body, err := TransformClaudeToGeminiWithOptions(claudeReq, "project-1", "gemini-2.5-flash", DefaultTransformOptions())
+	require.NoError(t, err)
+
+	var req V1InternalRequest
+	require.NoError(t, json.Unmarshal(body, &req))
+	require.Len(t, req.Request.Tools, 2)
+	require.Len(t, req.Request.Tools[0].FunctionDeclarations, 1)
+	require.Equal(t, "get_weather", req.Request.Tools[0].FunctionDeclarations[0].Name)
+	require.NotNil(t, req.Request.Tools[1].GoogleSearch)
+}

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
 				}
@@ -3169,12 +3171,17 @@ func convertClaudeToolsToGeminiTools(tools any) []any {
 		return nil
 	}
 
+	hasWebSearch := false
 	funcDecls := make([]any, 0, len(arr))
 	for _, t := range arr {
 		tm, ok := t.(map[string]any)
 		if !ok {
 			continue
 		}
+		if isClaudeWebSearchToolMap(tm) {
+			hasWebSearch = true
+			continue
+		}
 
 		var name, desc string
 		var params any
@@ -3218,13 +3225,75 @@ func convertClaudeToolsToGeminiTools(tools any) []any {
 		})
 	}
 
-	if len(funcDecls) == 0 {
+	out := make([]any, 0, 2)
+	if len(funcDecls) > 0 {
+		out = append(out, map[string]any{
+			"functionDeclarations": funcDecls,
+		})
+	}
+	if hasWebSearch {
+		out = append(out, map[string]any{
+			"googleSearch": map[string]any{},
+		})
+	}
+	if len(out) == 0 {
 		return nil
 	}
-	return []any{
-		map[string]any{
-			"functionDeclarations": funcDecls,
-		},
+	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" {
+		return true
+	}
+
+	name, _ := tool["name"].(string)
+	switch strings.TrimSpace(name) {
+	case "web_search", "google_search", "web_search_20250305":
+		return true
+	default:
+		return false
 	}
 }
 

backend/internal/service/gemini_messages_compat_service_test.go

@@ -164,6 +164,35 @@ func TestConvertClaudeToolsToGeminiTools_CustomType(t *testing.T) {
 	}
 }
 
+func TestConvertClaudeToolsToGeminiTools_PreservesWebSearchAlongsideFunctions(t *testing.T) {
+	tools := []any{
+		map[string]any{
+			"name":         "get_weather",
+			"description":  "Get weather info",
+			"input_schema": map[string]any{"type": "object"},
+		},
+		map[string]any{
+			"type": "web_search_20250305",
+			"name": "web_search",
+		},
+	}
+
+	result := convertClaudeToolsToGeminiTools(tools)
+	require.Len(t, result, 2)
+
+	functionDecl, ok := result[0].(map[string]any)
+	require.True(t, ok)
+	funcDecls, ok := functionDecl["functionDeclarations"].([]any)
+	require.True(t, ok)
+	require.Len(t, funcDecls, 1)
+
+	searchDecl, ok := result[1].(map[string]any)
+	require.True(t, ok)
+	googleSearch, ok := searchDecl["googleSearch"].(map[string]any)
+	require.True(t, ok)
+	require.Empty(t, googleSearch)
+}
+
 func TestGeminiHandleNativeNonStreamingResponse_DebugDisabledDoesNotEmitHeaderLogs(t *testing.T) {
 	gin.SetMode(gin.TestMode)
 	logSink, restore := captureStructuredLog(t)
@@ -232,6 +261,53 @@ func TestGeminiMessagesCompatServiceForward_PreservesRequestedModelAndMappedUpst
 	require.Contains(t, httpStub.lastReq.URL.String(), "/models/claude-sonnet-4-20250514:")
 }
 
+func TestGeminiMessagesCompatServiceForward_NormalizesWebSearchToolForAIStudio(t *testing.T) {
+	gin.SetMode(gin.TestMode)
+	w := httptest.NewRecorder()
+	c, _ := gin.CreateTestContext(w)
+	c.Request = httptest.NewRequest(http.MethodPost, "/v1/messages", nil)
+
+	httpStub := &geminiCompatHTTPUpstreamStub{
+		response: &http.Response{
+			StatusCode: http.StatusOK,
+			Header:     http.Header{"x-request-id": []string{"gemini-req-2"}},
+			Body:       io.NopCloser(strings.NewReader(`{"candidates":[{"content":{"parts":[{"text":"hello"}]}}],"usageMetadata":{"promptTokenCount":10,"candidatesTokenCount":5}}`)),
+		},
+	}
+	svc := &GeminiMessagesCompatService{httpUpstream: httpStub, cfg: &config.Config{}}
+	account := &Account{
+		ID:   1,
+		Type: AccountTypeAPIKey,
+		Credentials: map[string]any{
+			"api_key": "test-key",
+		},
+	}
+	body := []byte(`{"model":"claude-sonnet-4","max_tokens":16,"messages":[{"role":"user","content":"hello"}],"tools":[{"name":"get_weather","description":"Get weather info","input_schema":{"type":"object"}},{"type":"web_search_20250305","name":"web_search"}]}`)
+
+	result, err := svc.Forward(context.Background(), c, account, body)
+	require.NoError(t, err)
+	require.NotNil(t, result)
+	require.NotNil(t, httpStub.lastReq)
+
+	postedBody, err := io.ReadAll(httpStub.lastReq.Body)
+	require.NoError(t, err)
+
+	var posted map[string]any
+	require.NoError(t, json.Unmarshal(postedBody, &posted))
+	tools, ok := posted["tools"].([]any)
+	require.True(t, ok)
+	require.Len(t, tools, 2)
+
+	searchTool, ok := tools[1].(map[string]any)
+	require.True(t, ok)
+	_, hasSnake := searchTool["google_search"]
+	_, hasCamel := searchTool["googleSearch"]
+	require.True(t, hasSnake)
+	require.False(t, hasCamel)
+	_, hasFuncDecl := searchTool["functionDeclarations"]
+	require.False(t, hasFuncDecl)
+}
+
 func TestConvertClaudeMessagesToGeminiGenerateContent_AddsThoughtSignatureForToolUse(t *testing.T) {
 	claudeReq := map[string]any{
 		"model":      "claude-haiku-4-5-20251001",