feat: add support for google search and browsing tools

Author: reugn

README.md

@@ -96,6 +96,16 @@ An example of basic configuration:
       "threshold": "LOW"
     }
   ],
+  "tools": [
+    {
+      "name": "GOOGLE_SEARCH",
+      "enabled": true
+    },
+    {
+      "name": "URL_CONTEXT",
+      "enabled": true
+    }
+  ],
   "history": {
   }
 }

cmd/gemini/main.go

@@ -48,7 +48,7 @@ func run() int {
 		}
 
 		chatSession, err := gemini.NewChatSession(context.Background(), opts.GenerativeModel,
-			configuration.Data.GenaiSafetySettings())
+			configuration.Data.GenaiContentConfig())
 		if err != nil {
 			return err
 		}

gemini/chat_session.go

@@ -26,14 +26,14 @@ type ChatSession struct {
 }
 
 // NewChatSession returns a new [ChatSession].
-func NewChatSession(ctx context.Context, model string, safetySettings []*genai.SafetySetting) (*ChatSession, error) {
+func NewChatSession(ctx context.Context, model string,
+	contentConfig *genai.GenerateContentConfig) (*ChatSession, error) {
 	client, err := genai.NewClient(ctx, nil)
 	if err != nil {
 		return nil, fmt.Errorf("failed to create client: %w", err)
 	}
 
-	config := &genai.GenerateContentConfig{SafetySettings: safetySettings}
-	chat, err := client.Chats.Create(ctx, model, config, nil)
+	chat, err := client.Chats.Create(ctx, model, contentConfig, nil)
 	if err != nil {
 		return nil, fmt.Errorf("failed to create chat: %w", err)
 	}
@@ -42,7 +42,7 @@ func NewChatSession(ctx context.Context, model string, safetySettings []*genai.S
 		ctx:    ctx,
 		client: client,
 		chat:   chat,
-		config: config,
+		config: contentConfig,
 		model:  model,
 	}, nil
 }

internal/config/application_data.go

@@ -12,6 +12,11 @@ const (
 	thresholdOff    = "OFF"
 )
 
+const (
+	toolGoogleSearch = "GOOGLE_SEARCH"
+	toolURLContext   = "URL_CONTEXT"
+)
+
 // Threshold is a custom type that wraps genai.HarmBlockThreshold
 // and uses the custom string for serialization.
 type Threshold string
@@ -32,32 +37,45 @@ func (t Threshold) toGenai() genai.HarmBlockThreshold {
 }
 
 // SafetySetting is a custom type that wraps genai.SafetySetting
-// and uses the custom HarmBlockThreshold for serialization.
+// and uses the custom Threshold for serialization.
 type SafetySetting struct {
 	Category  genai.HarmCategory `json:"category"`
 	Threshold Threshold          `json:"threshold"`
 }
 
+// Tool represents a model tool configuration.
+type Tool struct {
+	Name    string `json:"name"`
+	Enabled bool   `json:"enabled"`
+}
+
 // ApplicationData encapsulates application state and configuration.
 // Note that the chat history is stored in plain text format.
 type ApplicationData struct {
 	SystemPrompts  map[string]gemini.SystemInstruction      `json:"system_prompts"`
-	SafetySettings []*SafetySetting                         `json:"safety_settings"`
+	SafetySettings []SafetySetting                          `json:"safety_settings"`
+	Tools          []Tool                                   `json:"tools"`
 	History        map[string][]*gemini.SerializableContent `json:"history"`
 }
 
 // newDefaultApplicationData returns a new ApplicationData with default values.
 func newDefaultApplicationData() *ApplicationData {
-	defaultSafetySettings := []*SafetySetting{
+	defaultSafetySettings := []SafetySetting{
 		{Category: genai.HarmCategoryHarassment, Threshold: thresholdLow},
 		{Category: genai.HarmCategoryHateSpeech, Threshold: thresholdLow},
 		{Category: genai.HarmCategorySexuallyExplicit, Threshold: thresholdLow},
 		{Category: genai.HarmCategoryDangerousContent, Threshold: thresholdLow},
 	}
 
+	defaultTools := []Tool{
+		{Name: toolGoogleSearch, Enabled: true},
+		{Name: toolURLContext, Enabled: true},
+	}
+
 	return &ApplicationData{
 		SystemPrompts:  make(map[string]gemini.SystemInstruction),
 		SafetySettings: defaultSafetySettings,
+		Tools:          defaultTools,
 		History:        make(map[string][]*gemini.SerializableContent),
 	}
 }
@@ -84,3 +102,36 @@ func (d *ApplicationData) GenaiSafetySettings() []*genai.SafetySetting {
 
 	return genaiSafetySettings
 }
+
+// GenaiTools builds a genai Tool slice using enabled entries.
+func (d *ApplicationData) GenaiTools() []*genai.Tool {
+	tools := make([]*genai.Tool, 0, len(d.Tools))
+	for _, tool := range d.Tools {
+		if !tool.Enabled {
+			continue
+		}
+
+		var genaiTool *genai.Tool
+		switch tool.Name {
+		case toolGoogleSearch:
+			genaiTool = &genai.Tool{GoogleSearch: &genai.GoogleSearch{}}
+		case toolURLContext:
+			genaiTool = &genai.Tool{URLContext: &genai.URLContext{}}
+		default:
+			continue // Skip unknown tools
+		}
+
+		tools = append(tools, genaiTool)
+	}
+
+	return tools
+}
+
+// GenaiContentConfig builds a genai GenerateContentConfig with the current
+// safety settings and enabled tools.
+func (d *ApplicationData) GenaiContentConfig() *genai.GenerateContentConfig {
+	return &genai.GenerateContentConfig{
+		SafetySettings: d.GenaiSafetySettings(),
+		Tools:          d.GenaiTools(),
+	}
+}