diff --git a/api_client.go b/api_client.go
index 64571b1a..0d1bd32d 100644
--- a/api_client.go
+++ b/api_client.go
@@ -34,10 +34,12 @@ import (
 	"time"
 )
 
-const maxChunkSize = 8 * 1024 * 1024 // 8 MB chunk size
-const maxRetryCount = 3
-const initialRetryDelay = time.Second
-const delayMultiplier = 2
+const (
+	maxChunkSize      = 8 * 1024 * 1024 // 8 MB chunk size
+	maxRetryCount     = 3
+	initialRetryDelay = time.Second
+	delayMultiplier   = 2
+)
 
 type apiClient struct {
 	clientConfig *ClientConfig
@@ -75,7 +77,6 @@ func sendStreamRequest[T responseStream[R], R any](ctx context.Context, ac *apiC
 
 // sendRequest issues an API request and returns a map of the response contents.
 func sendRequest(ctx context.Context, ac *apiClient, path string, method string, body map[string]any, httpOptions *HTTPOptions) (map[string]any, error) {
-
 	req, httpOptions, err := buildRequest(ctx, ac, path, body, method, httpOptions)
 	if err != nil {
 		return nil, err
@@ -435,7 +436,7 @@ func iterateResponseStream[R any](rs *responseStream[R], responseConverter func(
 			default:
 				var err error
 				if len(line) > 0 {
-					var respWithError = new(responseWithError)
+					respWithError := new(responseWithError)
 					// Stream chunk that doesn't matches error format.
 					if marshalErr := json.Unmarshal(line, respWithError); marshalErr != nil {
 						err = fmt.Errorf("iterateResponseStream: invalid stream chunk: %s:%s", string(prefix), string(data))
@@ -479,7 +480,7 @@ type responseWithError struct {
 }
 
 func newAPIError(resp *http.Response) error {
-	var respWithError = new(responseWithError)
+	respWithError := new(responseWithError)
 	body, err := io.ReadAll(resp.Body)
 	if err != nil {
 		return fmt.Errorf("newAPIError: error reading response body: %w. Response: %v", err, string(body))
@@ -561,7 +562,7 @@ func (ac *apiClient) uploadFile(ctx context.Context, r io.Reader, uploadURL stri
 	var offset int64 = 0
 	var resp *http.Response
 	var respBody map[string]any
-	var uploadCommand = "upload"
+	uploadCommand := "upload"
 
 	buffer := make([]byte, maxChunkSize)
 	for {
@@ -574,7 +575,7 @@ func (ac *apiClient) uploadFile(ctx context.Context, r io.Reader, uploadURL stri
 		} else if err != nil {
 			return nil, fmt.Errorf("Failed to read bytes from file at offset %d: %w. Bytes actually read: %d", offset, err, bytesRead)
 		}
-		for attempt := 0; attempt < maxRetryCount; attempt++ {
+		for attempt := range maxRetryCount {
 			patchedHTTPOptions, err := patchHTTPOptions(ac.clientConfig.HTTPOptions, *httpOptions)
 			if err != nil {
 				return nil, err
@@ -641,7 +642,7 @@ func (ac *apiClient) uploadFile(ctx context.Context, r io.Reader, uploadURL stri
 		return nil, fmt.Errorf("Failed to upload file: Upload status is not finalized")
 	}
 
-	var response = new(File)
+	response := new(File)
 	err := mapToStruct(respBody["file"].(map[string]any), &response)
 	if err != nil {
 		return nil, err
diff --git a/api_client_test.go b/api_client_test.go
index 43c71e0e..0e3fb7aa 100644
--- a/api_client_test.go
+++ b/api_client_test.go
@@ -658,11 +658,13 @@ func TestMapToStruct(t *testing.T) {
 			inputMap: map[string]any{
 				"role":     "test-role",
 				"TokenIDs": []string{"123", "456"},
-				"Tokens":   [][]byte{[]byte("token1"), []byte("token2")}},
+				"Tokens":   [][]byte{[]byte("token1"), []byte("token2")},
+			},
 			wantValue: TokensInfo{
 				Role:     "test-role",
 				TokenIDs: []int64{123, 456},
-				Tokens:   [][]byte{[]byte("token1"), []byte("token2")}},
+				Tokens:   [][]byte{[]byte("token1"), []byte("token2")},
+			},
 		},
 		{
 			name: "Citation",
@@ -705,7 +707,6 @@ func TestMapToStruct(t *testing.T) {
 			outputValue := reflect.New(reflect.TypeOf(tc.wantValue)).Interface()
 
 			err := mapToStruct(tc.inputMap, &outputValue)
-
 			if err != nil {
 				t.Fatalf("mapToStruct failed: %v", err)
 			}
@@ -1309,7 +1310,7 @@ func createTestFile(t *testing.T, size int64) (string, func()) {
 
 	buf := make([]byte, 1024*1024) // 1MB buffer
 	pattern := []byte("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789!@#$%^&*()")
-	for i := 0; i < len(buf); i++ {
+	for i := range buf {
 		buf[i] = pattern[i%len(pattern)]
 	}
 
@@ -1504,7 +1505,6 @@ func TestUploadFile(t *testing.T) {
 			uploadURL := server.URL + "/upload"
 
 			uploadedFile, err := ac.uploadFile(ctx, fileReader, uploadURL, httpOpts)
-
 			if err != nil {
 				t.Fatalf("uploadFile failed: %v", err)
 			}
@@ -1530,7 +1530,6 @@ func TestUploadFile(t *testing.T) {
 			if uploadedFile.MIMEType != "text/plain" { // Matches mock server response
 				t.Errorf("uploadedFile.MIMEType mismatch: want 'text/plain', got '%s'", uploadedFile.MIMEType)
 			}
-
 		})
 	}
 }
diff --git a/base_url.go b/base_url.go
index 378370c5..71a4562c 100644
--- a/base_url.go
+++ b/base_url.go
@@ -14,8 +14,10 @@
 
 package genai
 
-var defaultBaseGeminiURL string = ""
-var defaultBaseVertexURL string = ""
+var (
+	defaultBaseGeminiURL string = ""
+	defaultBaseVertexURL string = ""
+)
 
 // BaseURLParameters are parameters for setting the base URLs for the Gemini API and Vertex AI API.
 type BaseURLParameters struct {
diff --git a/caches_test.go b/caches_test.go
index 24536fa8..a6ffc809 100644
--- a/caches_test.go
+++ b/caches_test.go
@@ -91,7 +91,8 @@ func TestCachesAll(t *testing.T) {
 			defer ts.Close()
 
 			// Create a client with the test server
-			client, err := NewClient(context.Background(), &ClientConfig{HTTPOptions: HTTPOptions{BaseURL: ts.URL},
+			client, err := NewClient(context.Background(), &ClientConfig{
+				HTTPOptions: HTTPOptions{BaseURL: ts.URL},
 				envVarProvider: func() map[string]string {
 					return map[string]string{
 						"GOOGLE_API_KEY": "test-api-key",
diff --git a/chats_test.go b/chats_test.go
index 7205d859..b16d4553 100644
--- a/chats_test.go
+++ b/chats_test.go
@@ -35,9 +35,9 @@ func TestValidateContent(t *testing.T) {
 		{"NilContent", nil, false},
 		{"EmptyParts", &Content{Parts: []*Part{}}, false},
 		{"NilPart", &Content{Parts: []*Part{nil}}, false},
-		{"EmptyTextPart", &Content{Parts: []*Part{&Part{Text: ""}}}, false},
-		{"ValidTextPart", &Content{Parts: []*Part{&Part{Text: "hello"}}}, true},
-		{"ValidFunctionCall", &Content{Parts: []*Part{&Part{FunctionCall: &FunctionCall{Name: "test"}}}}, true},
+		{"EmptyTextPart", &Content{Parts: []*Part{{Text: ""}}}, false},
+		{"ValidTextPart", &Content{Parts: []*Part{{Text: "hello"}}}, true},
+		{"ValidFunctionCall", &Content{Parts: []*Part{{FunctionCall: &FunctionCall{Name: "test"}}}}, true},
 	}
 
 	for _, tt := range tests {
@@ -176,7 +176,6 @@ func TestChatsUnitTest(t *testing.T) {
 			break
 		}
 	})
-
 }
 
 func TestChatsText(t *testing.T) {
@@ -316,16 +315,16 @@ func TestChatsHistory(t *testing.T) {
 			// Create a new Chat with handwritten history.
 			var config *GenerateContentConfig = &GenerateContentConfig{Temperature: Ptr[float32](0.5)}
 			history := []*Content{
-				&Content{
+				{
 					Role: "user",
 					Parts: []*Part{
-						&Part{Text: "What is 1 + 2?"},
+						{Text: "What is 1 + 2?"},
 					},
 				},
-				&Content{
+				{
 					Role: "model",
 					Parts: []*Part{
-						&Part{Text: "3"},
+						{Text: "3"},
 					},
 				},
 			}
@@ -721,10 +720,10 @@ data:{
 		}
 
 		var expectedResponses []*Content
-		expectedResponses = append(expectedResponses, &Content{Role: "model", Parts: []*Part{&Part{Text: "text1_candidate1"}}})
-		expectedResponses = append(expectedResponses, &Content{Role: "model", Parts: []*Part{&Part{Text: " "}}})
-		expectedResponses = append(expectedResponses, &Content{Role: "model", Parts: []*Part{&Part{Text: "text3_candidate1"}, &Part{Text: " additional text3_candidate1 "}}})
-		expectedResponses = append(expectedResponses, &Content{Role: "model", Parts: []*Part{&Part{Text: "text4_candidate1"}, &Part{Text: " additional text4_candidate1"}}})
+		expectedResponses = append(expectedResponses, &Content{Role: "model", Parts: []*Part{{Text: "text1_candidate1"}}})
+		expectedResponses = append(expectedResponses, &Content{Role: "model", Parts: []*Part{{Text: " "}}})
+		expectedResponses = append(expectedResponses, &Content{Role: "model", Parts: []*Part{{Text: "text3_candidate1"}, {Text: " additional text3_candidate1 "}}})
+		expectedResponses = append(expectedResponses, &Content{Role: "model", Parts: []*Part{{Text: "text4_candidate1"}, {Text: " additional text4_candidate1"}}})
 
 		history := chat.History(false)
 		expectedUserMessage := "What is 1 + 2?"
@@ -738,6 +737,5 @@ data:{
 				}
 			}
 		}
-
 	})
 }
diff --git a/client_test.go b/client_test.go
index 5af56153..89739923 100644
--- a/client_test.go
+++ b/client_test.go
@@ -28,7 +28,6 @@ import (
 
 // TestNewClient only runs in replay mode.
 func TestNewClient(t *testing.T) {
-
 	ctx := context.Background()
 	t.Run("VertexAI with default credentials", func(t *testing.T) {
 		// Needed for account default credential.
@@ -85,7 +84,8 @@ func TestNewClient(t *testing.T) {
 		})
 
 		t.Run("Explicit project and location takes precedence over project and location from environment when set VertexAI", func(t *testing.T) {
-			client, err := NewClient(ctx, &ClientConfig{Backend: BackendVertexAI, Project: "constructor-project", Location: "constructor-location",
+			client, err := NewClient(ctx, &ClientConfig{
+				Backend: BackendVertexAI, Project: "constructor-project", Location: "constructor-location",
 				envVarProvider: func() map[string]string {
 					return map[string]string{
 						"GOOGLE_CLOUD_PROJECT":  "env-project-id",
@@ -113,7 +113,8 @@ func TestNewClient(t *testing.T) {
 
 		t.Run("API key from config when set VertexAI", func(t *testing.T) {
 			apiKey := "test-api-key-constructor"
-			client, err := NewClient(ctx, &ClientConfig{Backend: BackendVertexAI, APIKey: apiKey,
+			client, err := NewClient(ctx, &ClientConfig{
+				Backend: BackendVertexAI, APIKey: apiKey,
 				envVarProvider: func() map[string]string {
 					return map[string]string{
 						"GOOGLE_API_KEY": "test-api-key-env",
@@ -139,7 +140,8 @@ func TestNewClient(t *testing.T) {
 
 		t.Run("API key from environment when set VertexAI", func(t *testing.T) {
 			apiKey := "test-api-key-env"
-			client, err := NewClient(ctx, &ClientConfig{Backend: BackendVertexAI,
+			client, err := NewClient(ctx, &ClientConfig{
+				Backend: BackendVertexAI,
 				envVarProvider: func() map[string]string {
 					return map[string]string{
 						"GOOGLE_API_KEY": apiKey,
@@ -165,7 +167,8 @@ func TestNewClient(t *testing.T) {
 
 		t.Run("Project from environment", func(t *testing.T) {
 			projectID := "test-project-env"
-			client, err := NewClient(ctx, &ClientConfig{Backend: BackendVertexAI, Location: "test-location",
+			client, err := NewClient(ctx, &ClientConfig{
+				Backend: BackendVertexAI, Location: "test-location",
 				envVarProvider: func() map[string]string {
 					return map[string]string{
 						"GOOGLE_CLOUD_PROJECT": projectID,
@@ -182,7 +185,8 @@ func TestNewClient(t *testing.T) {
 
 		t.Run("Location from GOOGLE_CLOUD_REGION environment", func(t *testing.T) {
 			location := "test-region-env"
-			client, err := NewClient(ctx, &ClientConfig{Project: "test-project", Backend: BackendVertexAI,
+			client, err := NewClient(ctx, &ClientConfig{
+				Project: "test-project", Backend: BackendVertexAI,
 				envVarProvider: func() map[string]string {
 					return map[string]string{
 						"GOOGLE_CLOUD_REGION": location,
@@ -199,12 +203,14 @@ func TestNewClient(t *testing.T) {
 
 		t.Run("Location from GOOGLE_CLOUD_LOCATION environment", func(t *testing.T) {
 			location := "test-location-env"
-			client, err := NewClient(ctx, &ClientConfig{Project: "test-project", Backend: BackendVertexAI,
+			client, err := NewClient(ctx, &ClientConfig{
+				Project: "test-project", Backend: BackendVertexAI,
 				envVarProvider: func() map[string]string {
 					return map[string]string{
 						"GOOGLE_CLOUD_LOCATION": location,
 					}
-				}})
+				},
+			})
 			if err != nil {
 				t.Fatalf("Expected no error, got %v", err)
 			}
@@ -214,7 +220,8 @@ func TestNewClient(t *testing.T) {
 		})
 
 		t.Run("VertexAI set from environment", func(t *testing.T) {
-			client, err := NewClient(ctx, &ClientConfig{Project: "test-project", Location: "test-location",
+			client, err := NewClient(ctx, &ClientConfig{
+				Project: "test-project", Location: "test-location",
 				envVarProvider: func() map[string]string {
 					return map[string]string{
 						"GOOGLE_GENAI_USE_VERTEXAI": "true",
@@ -230,7 +237,8 @@ func TestNewClient(t *testing.T) {
 		})
 
 		t.Run("VertexAI false from environment", func(t *testing.T) {
-			client, err := NewClient(ctx, &ClientConfig{APIKey: "test-api-key",
+			client, err := NewClient(ctx, &ClientConfig{
+				APIKey: "test-api-key",
 				envVarProvider: func() map[string]string {
 					return map[string]string{
 						"GOOGLE_GENAI_USE_VERTEXAI": "false",
@@ -246,7 +254,8 @@ func TestNewClient(t *testing.T) {
 		})
 
 		t.Run("VertexAI from config", func(t *testing.T) {
-			client, err := NewClient(ctx, &ClientConfig{Backend: BackendVertexAI, Project: "test-project", Location: "test-location",
+			client, err := NewClient(ctx, &ClientConfig{
+				Backend: BackendVertexAI, Project: "test-project", Location: "test-location",
 				envVarProvider: func() map[string]string {
 					return map[string]string{
 						"GOOGLE_GENAI_USE_VERTEXAI": "false",
@@ -262,7 +271,8 @@ func TestNewClient(t *testing.T) {
 		})
 
 		t.Run("VertexAI is unset from config and environment is false", func(t *testing.T) {
-			client, err := NewClient(ctx, &ClientConfig{APIKey: "test-api-key",
+			client, err := NewClient(ctx, &ClientConfig{
+				APIKey: "test-api-key",
 				envVarProvider: func() map[string]string {
 					return map[string]string{
 						"GOOGLE_GENAI_USE_VERTEXAI": "false",
@@ -278,7 +288,8 @@ func TestNewClient(t *testing.T) {
 		})
 
 		t.Run("VertexAI is unset from config but environment is true", func(t *testing.T) {
-			client, err := NewClient(ctx, &ClientConfig{Backend: BackendGeminiAPI, APIKey: "test-api-key",
+			client, err := NewClient(ctx, &ClientConfig{
+				Backend: BackendGeminiAPI, APIKey: "test-api-key",
 				envVarProvider: func() map[string]string {
 					return map[string]string{
 						"GOOGLE_GENAI_USE_VERTEXAI": "true",
@@ -296,7 +307,8 @@ func TestNewClient(t *testing.T) {
 		t.Run("API key from constructor takes precedence over proj/location from environment", func(t *testing.T) {
 			// Vertex AI API key combo 1
 			apiKey := "vertexai-api-key"
-			client, err := NewClient(ctx, &ClientConfig{Backend: BackendVertexAI, APIKey: apiKey,
+			client, err := NewClient(ctx, &ClientConfig{
+				Backend: BackendVertexAI, APIKey: apiKey,
 				envVarProvider: func() map[string]string {
 					return map[string]string{
 						"GOOGLE_API_KEY":        "",
@@ -331,7 +343,8 @@ func TestNewClient(t *testing.T) {
 			// Vertex AI API key combo 2
 			project := "test-project"
 			location := "test-location"
-			client, err := NewClient(ctx, &ClientConfig{Backend: BackendVertexAI, Project: project, Location: location,
+			client, err := NewClient(ctx, &ClientConfig{
+				Backend: BackendVertexAI, Project: project, Location: location,
 				envVarProvider: func() map[string]string {
 					return map[string]string{
 						"GOOGLE_API_KEY":        "vertexai-api-key-env",
@@ -366,7 +379,8 @@ func TestNewClient(t *testing.T) {
 			// Vertex AI API key combo 3
 			project := "test-project-env"
 			location := "test-location-env"
-			client, err := NewClient(ctx, &ClientConfig{Backend: BackendVertexAI,
+			client, err := NewClient(ctx, &ClientConfig{
+				Backend: BackendVertexAI,
 				envVarProvider: func() map[string]string {
 					return map[string]string{
 						"GOOGLE_API_KEY":        "vertexai-api-key-env",
@@ -399,10 +413,12 @@ func TestNewClient(t *testing.T) {
 
 		t.Run("Base URL from HTTPOptions", func(t *testing.T) {
 			baseURL := "https://test-base-url.com/"
-			client, err := NewClient(ctx, &ClientConfig{Project: "test-project", Location: "test-location", Backend: BackendVertexAI,
+			client, err := NewClient(ctx, &ClientConfig{
+				Project: "test-project", Location: "test-location", Backend: BackendVertexAI,
 				HTTPOptions: HTTPOptions{
 					BaseURL: baseURL,
-				}})
+				},
+			})
 			if err != nil {
 				t.Fatalf("Expected no error, got %v", err)
 			}
@@ -431,12 +447,14 @@ func TestNewClient(t *testing.T) {
 
 		t.Run("Base URL from environment", func(t *testing.T) {
 			baseURL := "https://test-base-url.com/"
-			client, err := NewClient(ctx, &ClientConfig{Project: "test-project", Location: "test-location", Backend: BackendVertexAI,
+			client, err := NewClient(ctx, &ClientConfig{
+				Project: "test-project", Location: "test-location", Backend: BackendVertexAI,
 				envVarProvider: func() map[string]string {
 					return map[string]string{
 						"GOOGLE_VERTEX_BASE_URL": baseURL,
 					}
-				}})
+				},
+			})
 			if err != nil {
 				t.Fatalf("Expected no error, got %v", err)
 			}
@@ -469,7 +487,8 @@ func TestNewClient(t *testing.T) {
 
 		t.Run("API Key from config", func(t *testing.T) {
 			apiKey := "test-constructor-api-key"
-			client, err := NewClient(ctx, &ClientConfig{APIKey: apiKey,
+			client, err := NewClient(ctx, &ClientConfig{
+				APIKey: apiKey,
 				envVarProvider: func() map[string]string {
 					return map[string]string{
 						"GOOGLE_API_KEY": "test-env-api-key",
@@ -493,7 +512,8 @@ func TestNewClient(t *testing.T) {
 
 		t.Run("API Key from GOOGLE_API_KEY only", func(t *testing.T) {
 			apiKey := "test-api-key-env"
-			client, err := NewClient(ctx, &ClientConfig{Backend: BackendGeminiAPI,
+			client, err := NewClient(ctx, &ClientConfig{
+				Backend: BackendGeminiAPI,
 				envVarProvider: func() map[string]string {
 					return map[string]string{
 						"GOOGLE_API_KEY": apiKey,
@@ -509,7 +529,8 @@ func TestNewClient(t *testing.T) {
 		})
 		t.Run("API Key from GEMINI_API_KEY only", func(t *testing.T) {
 			apiKey := "test-api-key-env"
-			client, err := NewClient(ctx, &ClientConfig{Backend: BackendGeminiAPI,
+			client, err := NewClient(ctx, &ClientConfig{
+				Backend: BackendGeminiAPI,
 				envVarProvider: func() map[string]string {
 					return map[string]string{
 						"GEMINI_API_KEY": apiKey,
@@ -526,7 +547,8 @@ func TestNewClient(t *testing.T) {
 
 		t.Run("API Key from GEMINI_API_KEY and GOOGLE_API_KEY as empty string", func(t *testing.T) {
 			apiKey := "test-api-key-env"
-			client, err := NewClient(ctx, &ClientConfig{Backend: BackendGeminiAPI,
+			client, err := NewClient(ctx, &ClientConfig{
+				Backend: BackendGeminiAPI,
 				envVarProvider: func() map[string]string {
 					return map[string]string{
 						"GOOGLE_API_KEY": "",
@@ -545,7 +567,8 @@ func TestNewClient(t *testing.T) {
 		t.Run("API Key both GEMINI_API_KEY and GOOGLE_API_KEY", func(t *testing.T) {
 			geminiAPIKey := "gemini-api-key-env"
 			googleAPIKey := "google-api-key-env"
-			client, err := NewClient(ctx, &ClientConfig{Backend: BackendGeminiAPI,
+			client, err := NewClient(ctx, &ClientConfig{
+				Backend: BackendGeminiAPI,
 				envVarProvider: func() map[string]string {
 					return map[string]string{
 						"GOOGLE_API_KEY": googleAPIKey,
@@ -563,10 +586,12 @@ func TestNewClient(t *testing.T) {
 
 		t.Run("Base URL from HTTPOptions", func(t *testing.T) {
 			baseURL := "https://test-base-url.com/"
-			client, err := NewClient(ctx, &ClientConfig{APIKey: "test-api-key", Backend: BackendGeminiAPI,
+			client, err := NewClient(ctx, &ClientConfig{
+				APIKey: "test-api-key", Backend: BackendGeminiAPI,
 				HTTPOptions: HTTPOptions{
 					BaseURL: baseURL,
-				}})
+				},
+			})
 			if err != nil {
 				t.Fatalf("Expected no error, got %v", err)
 			}
@@ -595,12 +620,14 @@ func TestNewClient(t *testing.T) {
 
 		t.Run("Base URL from environment", func(t *testing.T) {
 			baseURL := "https://test-base-url.com/"
-			client, err := NewClient(ctx, &ClientConfig{APIKey: "test-api-key", Backend: BackendGeminiAPI,
+			client, err := NewClient(ctx, &ClientConfig{
+				APIKey: "test-api-key", Backend: BackendGeminiAPI,
 				envVarProvider: func() map[string]string {
 					return map[string]string{
 						"GOOGLE_GEMINI_BASE_URL": baseURL,
 					}
-				}})
+				},
+			})
 			if err != nil {
 				t.Fatalf("Expected no error, got %v", err)
 			}
@@ -690,7 +717,6 @@ func TestNewClient(t *testing.T) {
 			t.Errorf("Models.apiClient.clientConfig mismatch (-want +got):\n%s", diff)
 		}
 	})
-
 }
 
 func TestClientConfigHTTPOptions(t *testing.T) {
diff --git a/common.go b/common.go
index 413dc5d6..f5468947 100644
--- a/common.go
+++ b/common.go
@@ -21,6 +21,7 @@ import (
 	"fmt"
 	"iter"
 	"log"
+	"maps"
 	"net/http"
 	"net/url"
 	"reflect"
@@ -135,9 +136,7 @@ func setValueByPath(data map[string]any, keys []string, value any) {
 			if newMap, ok2 := value.(map[string]any); ok2 {
 				// Instead of overwriting dictionary with another dictionary, merge them.
 				// This is important for handling training and validation datasets in tuning.
-				for k, v := range newMap {
-					existingMap[k] = v
-				}
+				maps.Copy(existingMap, newMap)
 				data[finalKey] = existingMap // Assign the updated map back
 			}
 		} else {
@@ -147,9 +146,7 @@ func setValueByPath(data map[string]any, keys []string, value any) {
 		if finalKey == "_self" && reflect.TypeOf(value).Kind() == reflect.Map {
 			// Iterate through the `value` map and copy its contents to `data`.
 			if valMap, ok := value.(map[string]any); ok {
-				for k, v := range valMap {
-					data[k] = v
-				}
+				maps.Copy(data, valMap)
 			}
 		} else {
 			// If existing_data is None (or key doesn't exist), set the value directly.
diff --git a/common_test.go b/common_test.go
index 16cea1d9..f1f1d44a 100644
--- a/common_test.go
+++ b/common_test.go
@@ -21,9 +21,7 @@ import (
 	"github.com/google/go-cmp/cmp"
 )
 
-var (
-	dummyExtrasProvider = func(body map[string]any) map[string]any { return body }
-)
+var dummyExtrasProvider = func(body map[string]any) map[string]any { return body }
 
 func TestMergeHTTPOptions(t *testing.T) {
 	tests := []struct {
@@ -304,12 +302,10 @@ func TestSetValueByPath(t *testing.T) {
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-
 			setValueByPath(tt.data, tt.keys, tt.value)
 			if diff := cmp.Diff(tt.data, tt.want); diff != "" {
 				t.Errorf("setValueByPath() mismatch (-want +got):\n%s", diff)
 			}
-
 		})
 	}
 }
@@ -393,7 +389,6 @@ func TestGetValueByPath(t *testing.T) {
 					t.Errorf("getValueByPath() mismatch (-want +got):\n%s", diff)
 				}
 			}
-
 		})
 	}
 }
diff --git a/examples/batches/create_get_cancel.go b/examples/batches/create_get_cancel.go
index 6e402832..06af5b57 100644
--- a/examples/batches/create_get_cancel.go
+++ b/examples/batches/create_get_cancel.go
@@ -44,7 +44,7 @@ func run(ctx context.Context) {
 	}
 	if client.ClientConfig().Backend == genai.BackendVertexAI {
 		fmt.Println("Calling VertexAI Backend...")
-		var model = flag.String("model", "gemini-1.5-flash-002", "the model name, e.g. gemini-1.5-pro-002")
+		model := flag.String("model", "gemini-1.5-flash-002", "the model name, e.g. gemini-1.5-pro-002")
 		// Create a batch job.
 		result, err := client.Batches.Create(
 			ctx,
@@ -84,7 +84,7 @@ func run(ctx context.Context) {
 		fmt.Println("Cancelled batch job:", result.Name)
 	} else {
 		fmt.Println("Calling GeminiAPI Backend...")
-		var model = flag.String("model", "gemini-2.0-flash", "the model name, e.g. gemini-1.5-pro-002")
+		model := flag.String("model", "gemini-2.0-flash", "the model name, e.g. gemini-1.5-pro-002")
 		// Create a batch job.
 		result, err := client.Batches.Create(
 			ctx,
diff --git a/examples/caches/create_get_delete.go b/examples/caches/create_get_delete.go
index cca21652..7fb30670 100644
--- a/examples/caches/create_get_delete.go
+++ b/examples/caches/create_get_delete.go
@@ -70,7 +70,8 @@ func run(ctx context.Context) {
 					},
 				},
 			},
-		}})
+		},
+	})
 	if err != nil {
 		log.Fatal(err)
 	}
diff --git a/examples/files/upload_file.go b/examples/files/upload_file.go
index 9891609b..6d13de02 100644
--- a/examples/files/upload_file.go
+++ b/examples/files/upload_file.go
@@ -80,7 +80,7 @@ func run(ctx context.Context) {
 		fmt.Println("Calling GeminiAPI Backend...")
 	}
 	// Upload a new file.
-	var testDataDir = filepath.Join(moduleRootDir(), "testdata")
+	testDataDir := filepath.Join(moduleRootDir(), "testdata")
 	filePath := filepath.Join(testDataDir, "google.jpg")
 	file, err := client.Files.UploadFromPath(ctx, filePath, nil)
 	if err != nil {
diff --git a/examples/mcptoolbox/mcp_toolbox.go b/examples/mcptoolbox/mcp_toolbox.go
index bb994545..6212ca30 100644
--- a/examples/mcptoolbox/mcp_toolbox.go
+++ b/examples/mcptoolbox/mcp_toolbox.go
@@ -13,7 +13,6 @@ import (
 
 // ConvertToGenaiTool translates a ToolboxTool into the genai.FunctionDeclaration format.
 func ConvertToGenaiTool(toolboxTool *core.ToolboxTool) *genai.Tool {
-
 	inputschema, err := toolboxTool.InputSchema()
 	if err != nil {
 		return &genai.Tool{}
@@ -135,5 +134,4 @@ func main() {
 	}
 	log.Println("=== Final Response from Model (after processing function result) ===")
 	printResponse(finalResponse)
-
 }
diff --git a/examples/models/generate_content/function_declaration_json_schema.go b/examples/models/generate_content/function_declaration_json_schema.go
index 2c9f0bb8..6d7a24d5 100644
--- a/examples/models/generate_content/function_declaration_json_schema.go
+++ b/examples/models/generate_content/function_declaration_json_schema.go
@@ -29,7 +29,7 @@ import (
 var model = flag.String("model", "gemini-2.0-flash", "the model name, e.g. gemini-2.0-flash")
 
 func run(ctx context.Context) {
-	var parameterSchema = map[string]any{
+	parameterSchema := map[string]any{
 		"type": "object",
 		"properties": map[string]any{
 			"brightness": map[string]any{
@@ -44,7 +44,7 @@ func run(ctx context.Context) {
 		"required": []string{"brightness", "colorTemperature"},
 	}
 
-	var tools = []*genai.Tool{
+	tools := []*genai.Tool{
 		{
 			FunctionDeclarations: []*genai.FunctionDeclaration{
 				{
diff --git a/examples/models/generate_content/function_declaration_schema.go b/examples/models/generate_content/function_declaration_schema.go
index 795fc765..aaa47061 100644
--- a/examples/models/generate_content/function_declaration_schema.go
+++ b/examples/models/generate_content/function_declaration_schema.go
@@ -29,8 +29,7 @@ import (
 var model = flag.String("model", "gemini-2.0-flash", "the model name, e.g. gemini-2.0-flash")
 
 func run(ctx context.Context) {
-
-	var tools = []*genai.Tool{
+	tools := []*genai.Tool{
 		{
 			FunctionDeclarations: []*genai.FunctionDeclaration{
 				{
diff --git a/examples/models/generate_content/text_stream.go b/examples/models/generate_content/text_stream.go
index eb55837a..e0ae3552 100644
--- a/examples/models/generate_content/text_stream.go
+++ b/examples/models/generate_content/text_stream.go
@@ -37,7 +37,7 @@ func run(ctx context.Context) {
 	} else {
 		fmt.Println("Calling GeminiAI.GenerateContentStream API...")
 	}
-	var config *genai.GenerateContentConfig = &genai.GenerateContentConfig{SystemInstruction: &genai.Content{Parts: []*genai.Part{&genai.Part{Text: "You are a story writer."}}}}
+	var config *genai.GenerateContentConfig = &genai.GenerateContentConfig{SystemInstruction: &genai.Content{Parts: []*genai.Part{{Text: "You are a story writer."}}}}
 	// Call the GenerateContent method.
 	for result, err := range client.Models.GenerateContentStream(ctx, *model, genai.Text("Tell me a story in 300 words."), config) {
 		if err != nil {
diff --git a/examples/models/recontext_image/image.go b/examples/models/recontext_image/image.go
index 53aa187b..17fba516 100644
--- a/examples/models/recontext_image/image.go
+++ b/examples/models/recontext_image/image.go
@@ -58,7 +58,8 @@ func run(ctx context.Context) {
 		&genai.RecontextImageSource{
 			Prompt:        prompt,
 			PersonImage:   nil,
-			ProductImages: productImages},
+			ProductImages: productImages,
+		},
 		&genai.RecontextImageConfig{
 			OutputMIMEType: "image/jpeg",
 		},
@@ -79,7 +80,8 @@ func run(ctx context.Context) {
 		&genai.RecontextImageSource{
 			Prompt:        "",
 			PersonImage:   personImage,
-			ProductImages: productImages2},
+			ProductImages: productImages2,
+		},
 		&genai.RecontextImageConfig{
 			OutputMIMEType: "image/jpeg",
 		},
diff --git a/files_test.go b/files_test.go
index c4dc915a..627c9e61 100644
--- a/files_test.go
+++ b/files_test.go
@@ -245,7 +245,8 @@ func TestFilesAll(t *testing.T) {
 			}))
 			defer ts.Close()
 
-			client, err := NewClient(ctx, &ClientConfig{HTTPOptions: HTTPOptions{BaseURL: ts.URL},
+			client, err := NewClient(ctx, &ClientConfig{
+				HTTPOptions: HTTPOptions{BaseURL: ts.URL},
 				envVarProvider: func() map[string]string {
 					return map[string]string{
 						"GOOGLE_API_KEY": "test-api-key",
@@ -692,7 +693,7 @@ func TestFilesUploadFromPath(t *testing.T) {
 	tempDir := t.TempDir()
 	filePath := filepath.Join(tempDir, "testfile.txt")
 	fileContent := "Content for UploadFromPath test."
-	err = os.WriteFile(filePath, []byte(fileContent), 0644)
+	err = os.WriteFile(filePath, []byte(fileContent), 0o644)
 	if err != nil {
 		t.Fatalf("Failed to create temp file: %v", err)
 	}
@@ -754,7 +755,7 @@ func TestFilesUploadFromPath(t *testing.T) {
 			name: "Error - Unknown MIME Type",
 			path: func() string { // Create a file with an unknown extension
 				p := filepath.Join(tempDir, "file.unknownext")
-				_ = os.WriteFile(p, []byte("data"), 0644)
+				_ = os.WriteFile(p, []byte("data"), 0o644)
 				return p
 			}(),
 			config:     nil, // No MIME override
diff --git a/internal/changefinder/main.go b/internal/changefinder/main.go
index bb8ecf85..ee922ab2 100644
--- a/internal/changefinder/main.go
+++ b/internal/changefinder/main.go
@@ -156,7 +156,7 @@ func touchModule(root, mod string) error {
 	c := exec.Command("echo")
 	log.Printf(c.String())
 
-	f, err := os.OpenFile(path.Join(root, mod, "CHANGES.md"), os.O_APPEND|os.O_WRONLY, 0644)
+	f, err := os.OpenFile(path.Join(root, mod, "CHANGES.md"), os.O_APPEND|os.O_WRONLY, 0o644)
 	if err != nil {
 		return err
 	}
diff --git a/live.go b/live.go
index e73e6b48..62d49bad 100644
--- a/live.go
+++ b/live.go
@@ -291,7 +291,7 @@ func (s *Session) Receive() (*LiveServerMessage, error) {
 		return nil, err
 	}
 
-	var message = new(LiveServerMessage)
+	message := new(LiveServerMessage)
 	err = mapToStruct(responseMap, message)
 	if err != nil {
 		return nil, err
diff --git a/live_test.go b/live_test.go
index 31a7a394..1878b5f3 100644
--- a/live_test.go
+++ b/live_test.go
@@ -194,7 +194,7 @@ func TestLiveConnect(t *testing.T) {
 
 	for _, tt := range connectTests {
 		t.Run(tt.desc, func(t *testing.T) {
-			var upgrader = websocket.Upgrader{}
+			upgrader := websocket.Upgrader{}
 			ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 				conn, _ := upgrader.Upgrade(w, r, nil)
 				defer conn.Close()
@@ -213,7 +213,6 @@ func TestLiveConnect(t *testing.T) {
 				}
 
 				mt, message, err := conn.ReadMessage()
-
 				if err != nil {
 					if tt.wantErr {
 						return
@@ -500,7 +499,7 @@ func TestLiveConnect(t *testing.T) {
 func setupTestWebsocketServer(t *testing.T, wantRequestBodySlice []string, fakeResponseBodySlice []string) *httptest.Server {
 	t.Helper()
 
-	var upgrader = websocket.Upgrader{}
+	upgrader := websocket.Upgrader{}
 
 	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		conn, _ := upgrader.Upgrade(w, r, nil)
diff --git a/main_test.go b/main_test.go
index 55c51be1..4dde54d9 100644
--- a/main_test.go
+++ b/main_test.go
@@ -30,10 +30,10 @@ var (
 		"mldev/models/generate_images/test_all_vertexai_config_person_generation_enum_parameters_3",
 	}
 	disabledTestsByMode = map[string][]string{
-		apiMode: []string{
+		apiMode: {
 			"TestModelsGenerateContentAudio/",
 		},
-		replayMode: []string{
+		replayMode: {
 			// TODO(b/372730941): httpOptions related tests are not covered in replay mode.
 			"models/delete/test_delete_model_with_http_options_in_method",
 			"models/generate_content/test_http_options_in_method",
@@ -60,7 +60,7 @@ var (
 			// filter=display_name%3A%22genai_%2A%22&pageSize=5 are reordered and mismatched
 			"batches/list/test_list_batch_jobs_with_config",
 		},
-		unitMode: []string{
+		unitMode: {
 			// We don't run table tests in unit mode.
 			"TestTable/",
 		},
diff --git a/models_test.go b/models_test.go
index 7c0a2252..d9692c5b 100644
--- a/models_test.go
+++ b/models_test.go
@@ -466,7 +466,8 @@ func TestModelsAll(t *testing.T) {
 			}))
 			defer ts.Close()
 
-			client, err := NewClient(ctx, &ClientConfig{HTTPOptions: HTTPOptions{BaseURL: ts.URL},
+			client, err := NewClient(ctx, &ClientConfig{
+				HTTPOptions: HTTPOptions{BaseURL: ts.URL},
 				envVarProvider: func() map[string]string {
 					return map[string]string{
 						"GOOGLE_API_KEY": "test-api-key",
@@ -544,7 +545,8 @@ func TestModelsAllEmptyResponse(t *testing.T) {
 			}))
 			defer ts.Close()
 
-			client, err := NewClient(ctx, &ClientConfig{HTTPOptions: HTTPOptions{BaseURL: ts.URL},
+			client, err := NewClient(ctx, &ClientConfig{
+				HTTPOptions: HTTPOptions{BaseURL: ts.URL},
 				envVarProvider: func() map[string]string {
 					return map[string]string{
 						"GOOGLE_API_KEY": "test-api-key",
diff --git a/pages.go b/pages.go
index c8b8f98c..bb20f125 100644
--- a/pages.go
+++ b/pages.go
@@ -18,6 +18,7 @@ import (
 	"context"
 	"errors"
 	"iter"
+	"maps"
 )
 
 // ErrPageDone is the error returned by an iterator's Next method when no more pages are available.
@@ -88,9 +89,7 @@ func (p Page[T]) Next(ctx context.Context) (Page[T], error) {
 		return p, ErrPageDone
 	}
 	c := make(map[string]any)
-	for k, v := range p.config {
-		c[k] = v
-	}
+	maps.Copy(c, p.config)
 	c["PageToken"] = p.NextPageToken
 
 	return newPage[T](ctx, p.Name, c, p.listFunc)
diff --git a/pages_test.go b/pages_test.go
index ecef819e..b676db60 100644
--- a/pages_test.go
+++ b/pages_test.go
@@ -137,7 +137,5 @@ func TestPageAll(t *testing.T) {
 
 			t.Fatalf("Unexpected error during iteration: %v", err)
 		}
-
 	}
-
 }
diff --git a/replay_sanitizer.go b/replay_sanitizer.go
index d12ee342..e4938c7e 100644
--- a/replay_sanitizer.go
+++ b/replay_sanitizer.go
@@ -60,7 +60,7 @@ func sanitizeMapWithSourceType(t *testing.T, sourceType reflect.Type, m any) {
 	for _, path := range paths {
 		if sourceType.Kind() == reflect.Slice {
 			data := m.([]any)
-			for i := 0; i < len(data); i++ {
+			for i := range data {
 				sanitizeMapByPath(data[i], path, stdBase64Handler, false)
 			}
 		} else {
diff --git a/replay_sanitizer_test.go b/replay_sanitizer_test.go
index 619d5e70..a16ada90 100644
--- a/replay_sanitizer_test.go
+++ b/replay_sanitizer_test.go
@@ -30,7 +30,7 @@ type nestedStruct struct {
 
 type outerStruct struct {
 	PointerField      *nestedStruct   `json:"pointerField,omitempty"`
-	StructField       nestedStruct    `json:"structField,omitempty"`
+	StructField       nestedStruct    `json:"structField"`
 	SliceField        []nestedStruct  `json:"sliceField,omitempty"`
 	SlicePointerField []*nestedStruct `json:"slicePointerField,omitempty"`
 	// Recursive types.
@@ -121,9 +121,9 @@ func TestSanitizeMapByPath(t *testing.T) {
 			sanitized: map[string]any{"k1": []any{"sanitized", "sanitized"}},
 		},
 		{
-			input:     map[string]any{"k1": []map[string]any{map[string]any{"k2": "v2"}, map[string]any{"k2": "v2"}}},
+			input:     map[string]any{"k1": []map[string]any{{"k2": "v2"}, {"k2": "v2"}}},
 			path:      "[]k1.k2",
-			sanitized: map[string]any{"k1": []map[string]any{map[string]any{"k2": "sanitized"}, map[string]any{"k2": "sanitized"}}},
+			sanitized: map[string]any{"k1": []map[string]any{{"k2": "sanitized"}, {"k2": "sanitized"}}},
 		},
 		{
 			input:     map[string]any{"k1": map[string]any{"k2": []any{"v2", "v2"}}},
@@ -147,9 +147,9 @@ func TestSanitizeMapByPath(t *testing.T) {
 			sanitized: map[string]any{"k1": []any{"v1", "v1"}},
 		},
 		{
-			input:     map[string]any{"k1": []map[string]any{map[string]any{"k2": "v2"}, map[string]any{"k2": "v2"}}},
+			input:     map[string]any{"k1": []map[string]any{{"k2": "v2"}, {"k2": "v2"}}},
 			path:      "[]wrongPath.k2",
-			sanitized: map[string]any{"k1": []map[string]any{map[string]any{"k2": "v2"}, map[string]any{"k2": "v2"}}},
+			sanitized: map[string]any{"k1": []map[string]any{{"k2": "v2"}, {"k2": "v2"}}},
 		},
 		{
 			input:     map[string]any{"k1": map[string]any{"k2": []string{"v2", "v2"}}},
diff --git a/table_test.go b/table_test.go
index 5783c60a..c287d26d 100644
--- a/table_test.go
+++ b/table_test.go
@@ -51,7 +51,7 @@ func snakeToCamel(s string) string {
 
 // methodParamType is extra mapping of method param name to its param type because reflect module cannot process private struct.
 var methodParamType = map[string]map[string]reflect.Type{
-	"editImage": map[string]reflect.Type{
+	"editImage": {
 		"referenceImages": reflect.TypeOf(([]ReferenceImage)(nil)),
 	},
 }
diff --git a/tokenizer/tokenizer.go b/tokenizer/tokenizer.go
index a26fa6fa..713fdb9c 100644
--- a/tokenizer/tokenizer.go
+++ b/tokenizer/tokenizer.go
@@ -404,11 +404,11 @@ func loadModelData(url string, wantHash string) ([]byte, error) {
 			return nil, fmt.Errorf("downloaded model hash mismatch")
 		}
 
-		err = os.MkdirAll(cacheDir, 0770)
+		err = os.MkdirAll(cacheDir, 0o770)
 		if err != nil {
 			return nil, fmt.Errorf("creating cache dir: %w", err)
 		}
-		err = os.WriteFile(cachePath, cacheData, 0660)
+		err = os.WriteFile(cachePath, cacheData, 0o660)
 		if err != nil {
 			return nil, fmt.Errorf("writing cache file: %w", err)
 		}
diff --git a/tokenizer/tokenizer_test.go b/tokenizer/tokenizer_test.go
index 6c808c91..f59aea64 100644
--- a/tokenizer/tokenizer_test.go
+++ b/tokenizer/tokenizer_test.go
@@ -59,8 +59,8 @@ func TestLoadModelData(t *testing.T) {
 	// Overwrite cache file with wrong data, and try again.
 	cacheDir := filepath.Join(os.TempDir(), "vertexai_tokenizer_model")
 	cachePath := filepath.Join(cacheDir, hashString([]byte(config.modelURL)))
-	_ = os.MkdirAll(cacheDir, 0770)
-	_ = os.WriteFile(cachePath, []byte{0, 1, 2, 3}, 0660)
+	_ = os.MkdirAll(cacheDir, 0o770)
+	_ = os.WriteFile(cachePath, []byte{0, 1, 2, 3}, 0o660)
 	data, err = loadModelData(config.modelURL, config.modelHash)
 	checkDataAndErr(data, err)
 }
@@ -92,7 +92,7 @@ func TestCreateLocalTokenizer(t *testing.T) {
 }
 
 func TestCountTokens(t *testing.T) {
-	var tests = []struct {
+	tests := []struct {
 		contents  []*genai.Content
 		wantCount int32
 	}{
diff --git a/transformer.go b/transformer.go
index 9571dc3a..e97f7478 100644
--- a/transformer.go
+++ b/transformer.go
@@ -139,6 +139,7 @@ func tLiveSpeechConfig(speechConfig any) (any, error) {
 		return nil, fmt.Errorf("unsupported speechConfig type: %T", speechConfig)
 	}
 }
+
 func tBytes(fromImageBytes any) (any, error) {
 	// TODO(b/389133914): Remove dummy bytes converter.
 	return fromImageBytes, nil
@@ -219,8 +220,8 @@ func tFileName(name any) (string, error) {
 					return "", fmt.Errorf("could not extract file name from URI: %s", name)
 				}
 				name = match[0]
-			} else if strings.HasPrefix(name, "files/") {
-				name = strings.TrimPrefix(name, "files/")
+			} else if after, ok := strings.CutPrefix(name, "files/"); ok {
+				name = after
 			}
 			return name, nil
 		}
diff --git a/tunings_test.go b/tunings_test.go
index ec499886..bc105819 100644
--- a/tunings_test.go
+++ b/tunings_test.go
@@ -117,6 +117,7 @@ func TestTuningsTuneUnit(t *testing.T) {
 		})
 	}
 }
+
 func TestTuningsTuneAPIMode(t *testing.T) {
 	if *mode != apiMode {
 		t.Skip("Skip. This test is only in the API mode")
@@ -164,7 +165,6 @@ func TestTuningsTuneAPIMode(t *testing.T) {
 
 		// Test tuning with a pre-tuned model.
 		continuousJob, err := client.Tunings.Tune(ctx, preTunedModelName, trainingDataset, nil)
-
 		if err != nil {
 			t.Fatalf("Tunings.Tune() with pre-tuned model failed: %v", err)
 		}
diff --git a/types_json_test.go b/types_json_test.go
index bf22a63f..9386002e 100644
--- a/types_json_test.go
+++ b/types_json_test.go
@@ -618,7 +618,7 @@ func TestMarshalJSON(t *testing.T) {
 				SizeBytes:      Ptr[int64](1024),
 				CreateTime:     time.Date(2024, 12, 31, 23, 59, 59, 0, time.UTC),
 				ExpirationTime: time.Date(2025, 12, 31, 23, 59, 59, 0, time.UTC),
-				UpdateTime:     time.Date(2025, 01, 01, 0, 0, 0, 0, time.UTC),
+				UpdateTime:     time.Date(2025, 0o1, 0o1, 0, 0, 0, 0, time.UTC),
 				Sha256Hash:     "test-hash",
 				URI:            "https://example.com/test-file",
 				DownloadURI:    "https://example.com/download/test-file",
@@ -759,13 +759,11 @@ func TestMarshalJSON(t *testing.T) {
 			if string(roundTripMarshal) != tt.want {
 				t.Errorf("%s.MarshalJSON() = %v, want %v", tt.target, string(roundTripMarshal), tt.want)
 			}
-
 		})
 	}
 }
 
 func TestJSONCustomTypes(t *testing.T) {
-
 	t.Run("int64SliceJSON", func(t *testing.T) {
 		type valueStruct struct {
 			Val int64SliceJSON `json:"val,omitempty"`
@@ -919,7 +917,7 @@ func TestJSONCustomTypes(t *testing.T) {
 
 	t.Run("dateJSON", func(t *testing.T) {
 		type valueStruct struct {
-			Val dateJSON `json:"val,omitempty"`
+			Val dateJSON `json:"val"`
 		}
 		type pointerStruct struct {
 			Val *dateJSON `json:"val,omitempty"`
diff --git a/version.go b/version.go
index 2a177888..9ca7d949 100644
--- a/version.go
+++ b/version.go
@@ -14,7 +14,5 @@
 
 package genai
 
-var (
-	// Version is the version of the SDK.
-	version = "1.29.0" // x-release-please-version
-)
+// Version is the version of the SDK.
+var version = "1.29.0" // x-release-please-version