diff --git a/pkg/cli/cmd.go b/pkg/cli/cmd.go
index 9116010..a00d1f5 100644
--- a/pkg/cli/cmd.go
+++ b/pkg/cli/cmd.go
@@ -17,8 +17,8 @@ var (
 func init() {
 	inputCmds := []*cobra.Command{newCmd, promptCmd, replyCmd}
 	for _, cmd := range inputCmds {
-		cmd.Flags().IntVar(&maxTokens, "length", config.OpenAI.DefaultMaxLength, "Max response length in tokens")
-		cmd.Flags().StringVar(&model, "model", config.OpenAI.DefaultModel, "The language model to use")
+		cmd.Flags().IntVar(&maxTokens, "length", *config.OpenAI.DefaultMaxLength, "Max response length in tokens")
+		cmd.Flags().StringVar(&model, "model", *config.OpenAI.DefaultModel, "The language model to use")
 	}
 
 	rootCmd.AddCommand(
diff --git a/pkg/cli/config.go b/pkg/cli/config.go
index 5e94dbb..b9c7137 100644
--- a/pkg/cli/config.go
+++ b/pkg/cli/config.go
@@ -9,10 +9,10 @@ import (
 )
 
 type Config struct {
-	OpenAI struct {
-		APIKey string `yaml:"apiKey"`
-		DefaultModel string `yaml:"defaultModel"`
-		DefaultMaxLength int `yaml:"defaultMaxLength"`
+	OpenAI *struct {
+		APIKey           *string `yaml:"apiKey" default:"your_key_here"`
+		DefaultModel     *string `yaml:"defaultModel" default:"gpt-4"`
+		DefaultMaxLength *int    `yaml:"defaultMaxLength" default:"256"`
 	} `yaml:"openai"`
 }
 
@@ -33,30 +33,30 @@ func getConfigDir() string {
 
 func NewConfig() (*Config, error) {
 	configFile := filepath.Join(getConfigDir(), "config.yaml")
+	shouldWriteDefaults := false
+	c := &Config{}
 
 	configBytes, err := os.ReadFile(configFile)
 	if os.IsNotExist(err) {
-		defaultConfig := &Config{}
-		defaultConfig.OpenAI.APIKey = "your_key_here"
+		shouldWriteDefaults = true
+	} else if err != nil {
+		return nil, fmt.Errorf("Could not read config file: %v", err)
+	} else {
+		yaml.Unmarshal(configBytes, c)
+	}
 
+	shouldWriteDefaults = SetStructDefaults(c)
+	if shouldWriteDefaults {
 		file, err := os.Create(configFile)
 		if err != nil {
 			return nil, fmt.Errorf("Could not open config file for writing: %v", err)
 		}
-
-		fmt.Printf("Writing default configuration to: %s\n", configFile)
-
-		bytes, _ := yaml.Marshal(defaultConfig)
-
+		bytes, _ := yaml.Marshal(c)
 		_, err = file.Write(bytes)
 		if err != nil {
 			return nil, fmt.Errorf("Could not save default configuration: %v", err)
 		}
-	} else if err != nil {
-		return nil, fmt.Errorf("Could not read config file: %v", err)
 	}
 
-	config := &Config{}
-	yaml.Unmarshal(configBytes, config)
-	return config, nil
+	return c, nil
 }
diff --git a/pkg/cli/openai.go b/pkg/cli/openai.go
index 09435e6..57f1407 100644
--- a/pkg/cli/openai.go
+++ b/pkg/cli/openai.go
@@ -27,7 +27,7 @@ func CreateChatCompletionRequest(model string, messages []Message, maxTokens int
 // CreateChatCompletion submits a Chat Completion API request and returns the
 // response.
 func CreateChatCompletion(model string, messages []Message, maxTokens int) (string, error) {
-	client := openai.NewClient(config.OpenAI.APIKey)
+	client := openai.NewClient(*config.OpenAI.APIKey)
 	req := CreateChatCompletionRequest(model, messages, maxTokens)
 	resp, err := client.CreateChatCompletion(context.Background(), req)
 	if err != nil {
@@ -40,7 +40,7 @@ func CreateChatCompletion(model string, messages []Message, maxTokens int) (stri
 // CreateChatCompletionStream submits a streaming Chat Completion API request
 // and streams the response to the provided output channel.
 func CreateChatCompletionStream(model string, messages []Message, maxTokens int, output chan string) error {
-	client := openai.NewClient(config.OpenAI.APIKey)
+	client := openai.NewClient(*config.OpenAI.APIKey)
 	req := CreateChatCompletionRequest(model, messages, maxTokens)
 
 	defer close(output)
diff --git a/pkg/cli/util.go b/pkg/cli/util.go
index 6157c48..11af566 100644
--- a/pkg/cli/util.go
+++ b/pkg/cli/util.go
@@ -4,6 +4,8 @@ import (
 	"fmt"
 	"os"
 	"os/exec"
+	"reflect"
+	"strconv"
 	"strings"
 	"time"
 )
@@ -51,8 +53,8 @@ func InputFromEditor(placeholder string, pattern string) (string, error) {
 	return strings.Trim(content, "\n \t"), nil
 }
 
-// humanTimeElapsedSince returns a human-friendly representation of the given time
-// duration.
+// humanTimeElapsedSince returns a human-friendly "in the past" representation
+// of the given duration.
 func humanTimeElapsedSince(d time.Duration) string {
 	seconds := d.Seconds()
 	minutes := seconds / 60
@@ -91,3 +93,68 @@ func humanTimeElapsedSince(d time.Duration) string {
 		return fmt.Sprintf("%d years ago", int64(years))
 	}
 }
+
+// SetStructDefaultValues checks for any nil ptr fields within the passed
+// struct, and sets the values of those fields to the value that is defined by
+// their "default" struct tag. Handles setting string, int, and bool values.
+// Returns whether any changes were made to the struct.
+func SetStructDefaults(data interface{}) bool {
+	v := reflect.ValueOf(data).Elem()
+	changed := false
+
+	for i := 0; i < v.NumField(); i++ {
+		field := v.Field(i)
+
+		// Check if we can set the field's value
+		if !field.CanSet() {
+			continue
+		}
+
+		// We won't bother with non-pointer fields
+		if field.Kind() != reflect.Ptr {
+			continue
+		}
+
+		t := field.Type() // type of pointer
+		e := t.Elem()     // type of value of pointer
+
+		// Handle nested structs recursively
+		if e.Kind() == reflect.Struct {
+			if field.IsNil() {
+				field.Set(reflect.New(e))
+				changed = true
+			}
+			result := SetStructDefaults(field.Interface())
+			if result {
+				changed = true
+			}
+			continue
+		}
+
+		if !field.IsNil() {
+			continue
+		}
+
+		// Get the "default" struct tag
+		defaultTag := v.Type().Field(i).Tag.Get("default")
+		if defaultTag == "" {
+			continue
+		}
+
+		// Set nil pointer fields to their defined defaults
+		switch e.Kind() {
+		case reflect.String:
+			defaultValue := defaultTag
+			field.Set(reflect.ValueOf(&defaultValue))
+		case reflect.Int, reflect.Int32, reflect.Int64:
+			intValue, _ := strconv.ParseInt(defaultTag, 10, 64)
+			field.Set(reflect.New(e))
+			field.Elem().SetInt(intValue)
+		case reflect.Bool:
+			boolValue := defaultTag == "true"
+			field.Set(reflect.ValueOf(&boolValue))
+		}
+		changed = true
+	}
+	return changed
+}