feat: add support for Google Search grounding as a tool type for Gemini models

internal/apischema/openai/openai.go

@@ -1076,11 +1076,27 @@ const (
 	ToolTypeFunction            ToolType = "function"
 	ToolTypeImageGeneration     ToolType = "image_generation"
 	ToolTypeEnterpriseWebSearch ToolType = "enterprise_search"
+	ToolTypeGoogleSearch        ToolType = "google_search"
 )
 
+// GCPGoogleSearchConfig contains GCP-specific configuration for Google Search grounding.
+// https://pkg.go.dev/google.golang.org/genai#GoogleSearch
+type GCPGoogleSearchConfig struct {
+	ExcludeDomains     []string            `json:"exclude_domains,omitempty"`     //nolint:tagliatelle
+	BlockingConfidence string              `json:"blocking_confidence,omitempty"` //nolint:tagliatelle
+	TimeRangeFilter    *GCPTimeRangeFilter `json:"time_range_filter,omitempty"`   //nolint:tagliatelle
+}
+
+// GCPTimeRangeFilter filters search results to a specific time range.
+type GCPTimeRangeFilter struct {
+	StartTime string `json:"start_time,omitempty"` //nolint:tagliatelle
+	EndTime   string `json:"end_time,omitempty"`   //nolint:tagliatelle
+}
+
 type Tool struct {
-	Type     ToolType            `json:"type"`
-	Function *FunctionDefinition `json:"function,omitempty"`
+	Type         ToolType               `json:"type"`
+	Function     *FunctionDefinition    `json:"function,omitempty"`
+	GoogleSearch *GCPGoogleSearchConfig `json:"google_search,omitempty"` //nolint:tagliatelle
 }
 
 // ToolChoiceType represents the type of tool choice.

internal/translator/gemini_helper.go

@@ -13,6 +13,7 @@ import (
 	"net/url"
 	"path"
 	"strings"
+	"time"
 
 	"github.com/google/uuid"
 	openaisdk "github.com/openai/openai-go/v2"
@@ -403,6 +404,20 @@ func openAIToolsToGeminiTools(openaiTools []openai.Tool, parametersJSONSchemaAva
 			genaiTools = append(genaiTools, genai.Tool{
 				EnterpriseWebSearch: &genai.EnterpriseWebSearch{},
 			})
+		case openai.ToolTypeGoogleSearch:
+			gs := &genai.GoogleSearch{}
+			if tool.GoogleSearch != nil {
+				gs.ExcludeDomains = tool.GoogleSearch.ExcludeDomains
+				if tool.GoogleSearch.BlockingConfidence != "" {
+					gs.BlockingConfidence = genai.PhishBlockThreshold(tool.GoogleSearch.BlockingConfidence)
+				}
+				if tool.GoogleSearch.TimeRangeFilter != nil {
+					gs.TimeRangeFilter = openAITimeRangeFilterToGemini(tool.GoogleSearch.TimeRangeFilter)
+				}
+			}
+			genaiTools = append(genaiTools, genai.Tool{
+				GoogleSearch: gs,
+			})
 		default:
 			return nil, fmt.Errorf("unsupported tool type: %s", tool.Type)
 		}
@@ -422,6 +437,24 @@ func openAIToolsToGeminiTools(openaiTools []openai.Tool, parametersJSONSchemaAva
 	return genaiTools, nil
 }
 
+func openAITimeRangeFilterToGemini(filter *openai.GCPTimeRangeFilter) *genai.Interval {
+	if filter == nil {
+		return nil
+	}
+	interval := &genai.Interval{}
+	if filter.StartTime != "" {
+		if t, err := time.Parse(time.RFC3339, filter.StartTime); err == nil {
+			interval.StartTime = t
+		}
+	}
+	if filter.EndTime != "" {
+		if t, err := time.Parse(time.RFC3339, filter.EndTime); err == nil {
+			interval.EndTime = t
+		}
+	}
+	return interval
+}
+
 // openAIToolChoiceToGeminiToolConfig converts OpenAI tool_choice to Gemini ToolConfig.
 // Example Input
 //

internal/translator/gemini_helper_test.go

@@ -8,6 +8,7 @@ package translator
 import (
 	"fmt"
 	"testing"
+	"time"
 
 	"github.com/google/go-cmp/cmp"
 	"github.com/google/go-cmp/cmp/cmpopts"
@@ -1637,6 +1638,128 @@ func TestOpenAIToolsToGeminiTools(t *testing.T) {
 				},
 			},
 		},
+		{
+			name: "google search tool only - no config",
+			openaiTools: []openai.Tool{
+				{
+					Type: openai.ToolTypeGoogleSearch,
+				},
+			},
+			parametersJSONSchemaAvailable: false,
+			expected: []genai.Tool{
+				{
+					GoogleSearch: &genai.GoogleSearch{},
+				},
+			},
+		},
+		{
+			name: "google search tool with exclude domains",
+			openaiTools: []openai.Tool{
+				{
+					Type: openai.ToolTypeGoogleSearch,
+					GoogleSearch: &openai.GCPGoogleSearchConfig{
+						ExcludeDomains: []string{"example.com", "test.com"},
+					},
+				},
+			},
+			parametersJSONSchemaAvailable: false,
+			expected: []genai.Tool{
+				{
+					GoogleSearch: &genai.GoogleSearch{
+						ExcludeDomains: []string{"example.com", "test.com"},
+					},
+				},
+			},
+		},
+		{
+			name: "google search tool with all options",
+			openaiTools: []openai.Tool{
+				{
+					Type: openai.ToolTypeGoogleSearch,
+					GoogleSearch: &openai.GCPGoogleSearchConfig{
+						ExcludeDomains:     []string{"spam.com"},
+						BlockingConfidence: "BLOCK_MEDIUM_AND_ABOVE",
+					},
+				},
+			},
+			parametersJSONSchemaAvailable: false,
+			expected: []genai.Tool{
+				{
+					GoogleSearch: &genai.GoogleSearch{
+						ExcludeDomains:     []string{"spam.com"},
+						BlockingConfidence: genai.PhishBlockThresholdBlockMediumAndAbove,
+					},
+				},
+			},
+		},
+		{
+			name: "google search tool with time range filter",
+			openaiTools: []openai.Tool{
+				{
+					Type: openai.ToolTypeGoogleSearch,
+					GoogleSearch: &openai.GCPGoogleSearchConfig{
+						TimeRangeFilter: &openai.GCPTimeRangeFilter{
+							StartTime: "2024-01-01T00:00:00Z",
+							EndTime:   "2024-12-31T23:59:59Z",
+						},
+					},
+				},
+			},
+			parametersJSONSchemaAvailable: false,
+			expected: []genai.Tool{
+				{
+					GoogleSearch: &genai.GoogleSearch{
+						TimeRangeFilter: &genai.Interval{
+							StartTime: time.Date(2024, 1, 1, 0, 0, 0, 0, time.UTC),
+							EndTime:   time.Date(2024, 12, 31, 23, 59, 59, 0, time.UTC),
+						},
+					},
+				},
+			},
+		},
+		{
+			name: "mixed function and google search tools",
+			openaiTools: []openai.Tool{
+				{
+					Type: openai.ToolTypeFunction,
+					Function: &openai.FunctionDefinition{
+						Name:        "search_products",
+						Description: "Search for products",
+						Parameters:  funcParams,
+					},
+				},
+				{
+					Type: openai.ToolTypeGoogleSearch,
+					GoogleSearch: &openai.GCPGoogleSearchConfig{
+						ExcludeDomains: []string{"competitor.com"},
+					},
+				},
+			},
+			parametersJSONSchemaAvailable: false,
+			expected: []genai.Tool{
+				{
+					GoogleSearch: &genai.GoogleSearch{
+						ExcludeDomains: []string{"competitor.com"},
+					},
+				},
+				{
+					FunctionDeclarations: []*genai.FunctionDeclaration{
+						{
+							Name:        "search_products",
+							Description: "Search for products",
+							Parameters: &genai.Schema{
+								Type: "object",
+								Properties: map[string]*genai.Schema{
+									"a": {Type: "integer"},
+									"b": {Type: "integer"},
+								},
+								Required: []string{"a", "b"},
+							},
+						},
+					},
+				},
+			},
+		},
 	}
 
 	for _, tc := range tests {

site/docs/capabilities/llm-integrations/vendor-specific-fields.md

@@ -38,6 +38,8 @@ The following backends support extension fields:
 - **Supported Fields**:
   - `safetySettings`: Configure the safety settings for gemini models that translates to `SafetySetting`. [Gemini Docs](https://docs.cloud.google.com/vertex-ai/generative-ai/docs/multimodal/configure-safety-filters)
   - `thinking`: Configure thinking process for reasoning models that automatically translates to `generationConfig.thinkingConfig`. [Gemini Docs](https://docs.cloud.google.com/vertex-ai/generative-ai/docs/thinking)
+- **Supported Tools**:
+  - `google_search`: Enable Google Search grounding for Gemini models. Configuration options vary by platform: `exclude_domains` and `blocking_confidence` are Vertex AI only, while `time_range_filter` is Gemini API only. [Google Search Grounding Docs](https://docs.cloud.google.com/vertex-ai/generative-ai/docs/grounding/grounding-with-google-search)
 
 ### GCP Anthropic
 
@@ -104,6 +106,52 @@ For more fine-grained control or provider-specific features, you can use the ven
 }
 ```
 
+### Using Google Search Grounding
+
+To enable Google Search grounding for Gemini models, add `google_search` to the tools array.
+
+For basic usage without configuration options:
+
+```json
+{
+  "model": "gemini-2.0-flash",
+  "messages": [
+    {
+      "role": "user",
+      "content": "What are the latest developments in quantum computing?"
+    }
+  ],
+  "tools": [
+    {
+      "type": "google_search"
+    }
+  ]
+}
+```
+
+For Vertex AI, you can add filtering options:
+
+```json
+{
+  "model": "gemini-2.0-flash",
+  "messages": [
+    {
+      "role": "user",
+      "content": "What are the latest developments in quantum computing?"
+    }
+  ],
+  "tools": [
+    {
+      "type": "google_search",
+      "google_search": {
+        "exclude_domains": ["example.com"],
+        "blocking_confidence": "BLOCK_LOW_AND_ABOVE"
+      }
+    }
+  ]
+}
+```
+
 ### Field Conflicts
 
 Vendor fields override translated fields when conflicts occur.