diff --git a/index.d.ts b/index.d.ts
index 7713977..57c0994 100644
--- a/index.d.ts
+++ b/index.d.ts
@@ -8,29 +8,107 @@
  */
 
 export interface AppConfig {
+
+  /**
+   * Application name (Example: restfulApiHandler)
+   */
   name: string,
+
+  /**
+   * Application description
+   */
   description: string,
+
+  /**
+   * Request prefix (Example: /api)
+   */
   prefix: string,
+
+  /**
+   * Use asynchronous handler?
+   */
   asynchronous: string,
+
+  /**
+   * Function timeout (in seconds)
+   */
   timeout: string,
+
+  /**
+   * AWS SDK for JavaScript version
+   */
   sdkVersion: string,
+
+  /**
+   * Node.js Lambda runtime identifier
+   */
   runtime: string
 }
 
+export interface PluginInfo {
+  [key: string]: any
+
+  /**
+   * Middleware plugin name.
+   */
+  name: string,
+
+  /**
+   * Github content URL
+   */
+  html_url: string
+}
+
 export interface TemplateVars {
+
   appName?: AppConfig['name'],
   appDescription?: AppConfig['description'],
   appPrefix?: AppConfig['prefix'],
   appTimeout?: AppConfig['timeout'],
   appRuntime?: AppConfig['runtime'],
-  pkgName?: string,
-  sdkPackage?: string,
-  cfResourceName?: string,
+
+  /**
+   * Package name (Example: restful-api-handler)
+   */
+  pkgName?: string | undefined,
+
+  /**
+   * AWS SDK mock library (Options: aws-sdk-client-mock|aws-sdk-mock)'
+   */
+  sdkPackage?: string | undefined,
+
+  /**
+   * CloudFront resource name
+   */
+  cfResourceName?: string | undefined,
+
+  /**
+   * Router path (Example: /api)
+   */
   routePath: string,
-  nodeVersion?: string
-}
 
-export interface PluginInfo {
-  name: string,
-  html_url: string
+  /**
+   * Node version number
+   */
+  nodeVersion?: string | undefined
 }
+
+/**
+ * Generate app sources from templates.
+ */
+export function createFiles(appConfig: AppConfig, outPath: string): Promise<void>
+
+/**
+ * Generate file source from a template.
+ */
+export function createFile(name: string, outPath: string, basePath: string): Promise<void>
+
+/**
+ * Install remote middleware
+ */
+export function addPackage(name: string): Promise<string|undefined>
+
+/**
+ * Request plugin list from the package repo.
+ */
+export function listPackages(): Promise<PluginInfo[]>