diff --git a/yeoman-generator/yeoman-generator-tests.ts b/yeoman-generator/yeoman-generator-tests.ts
new file mode 100644
index 000000000..84f007206
--- /dev/null
+++ b/yeoman-generator/yeoman-generator-tests.ts
@@ -0,0 +1,114 @@
+/// <reference path="yeoman-generator.d.ts" />
+import yeoman = require('yeoman-generator');
+
+var base = yeoman.generators.Base;
+var namedBase = yeoman.generators.NamedBase;
+
+var generator = base.extend({
+  initializing: function() {
+    return;
+  },
+  writing: {
+    app: function() {
+      return;
+    },
+    other: function() {
+      return;
+    }
+  },
+  end: function() {
+    return;
+  }
+});
+
+generator.argument('name', {
+  desc: 'desc',
+  required: true,
+  optional: true,
+  type: 'any',
+  defaults: 'any',
+});
+
+var compose = generator.composeWith('namespace', 'any', {
+  local: 'local',
+  link: 'link'
+});
+
+compose.defaultFor('name');
+compose.destinationRoot('rootPath') === 'string';
+compose.determineAppname();
+compose.getCollisionFilter()('output');
+compose.hookFor('name', {
+  as: 'string',
+  args: 'any',
+  options: 'any'
+});
+compose.option('name', {
+  alias: 'string',
+  defaults: 'any',
+  desc: 'string',
+  hide: true,
+  type: 'any'
+});
+var returnString: boolean;
+returnString = compose.rootGeneratorName() === 'string';
+compose.run('args');
+compose.run('args', () => {
+  return;
+});
+compose.runHooks(() => {
+  return;
+});
+returnString = compose.sourceRoot('rootPath') === 'string';
+
+var assert = yeoman.assert;
+
+assert.file('path');
+assert.file(['paths', 'paths']);
+assert.fileContent('file', /.*/);
+assert.fileContent([
+  ['string', /.*/],
+  ['string', /.*/],
+  ['string', /.*/]
+]);
+assert.files([
+  ['string', /.*/],
+  'string',
+  ['string', /.*/],
+  'string'
+]);
+assert.implement('subject', 'methods');
+assert.noFile('file');
+assert.noFileContent('file', /.*/);
+assert.noFileContent([
+  ['string', /.*/],
+  ['string', /.*/],
+  ['string', /.*/]
+]);
+assert.noImplement('subject', 'methods');
+assert.textEqual('value', 'expected');
+
+var test = yeoman.test;
+var dummyGen = test.createDummyGenerator();
+dummyGen.determineAppname();
+
+var createdGen = test.createGenerator('name', ['any', 'amy'], 'args', 'options');
+createdGen.determineAppname();
+
+test.decorate('context', 'method', () => {
+  return; // replacement
+}, 'options');
+test.gruntfile('options', () => {
+  return; // done
+});
+test.mockPrompt(createdGen, 'answers');
+test.registerDependencies(['dependencies', 'dependencies']);
+test.restore();
+var runContext = test.run('generator');
+
+runContext.async()();
+runContext.inDir('dirPath')
+  .withArguments('args')
+  .withGenerators(['deps', 'deps'])
+  .withOptions('opts')
+  .withPrompts('answers');
diff --git a/yeoman-generator/yeoman-generator.d.ts b/yeoman-generator/yeoman-generator.d.ts
new file mode 100644
index 000000000..aed7a8f03
--- /dev/null
+++ b/yeoman-generator/yeoman-generator.d.ts
@@ -0,0 +1,141 @@
+// Type definitions for yeoman-generator
+// Project: https://github.com/yeoman/generator
+// Definitions by: Kentaro Okuno <http://github.com/armorik83>
+// Definitions: https://github.com/borisyankov/DefinitelyTyped
+
+declare module yo {
+  export interface IYeomanGenerator {
+    argument(name: string, config: IArgumentConfig): void;
+    composeWith(namespace: string, options: any, settings?: IComposeSetting): IYeomanGenerator;
+    defaultFor(name: string): void;
+    destinationRoot(rootPath: string): string;
+    determineAppname(): void;
+    getCollisionFilter(): (output: any) => void;
+    hookFor(name: string, config: IHookConfig): void;
+    option(name: string, config: IYeomanGeneratorOption): void;
+    rootGeneratorName(): string;
+    run(args?: any): void;
+    run(args: any, callback?: Function): void;
+    runHooks(callback?: Function): void;
+    sourceRoot(rootPath: string): string;
+  }
+
+  export interface IArgumentConfig {
+    desc: string;
+    required: boolean;
+    optional: boolean;
+    type: any;
+    defaults: any;
+  }
+
+  export interface IComposeSetting {
+    local?: string;
+    link?: string;
+  }
+
+  export interface IHookConfig {
+    as: string;
+    args: any;
+    options: any;
+  }
+
+  export interface IYeomanGeneratorOption {
+    alias: string;
+    defaults: any;
+    desc: string;
+    hide: boolean;
+    type: any;
+  }
+
+  export interface IQueueProps {
+    initializing: () => void;
+    prompting?: () => void;
+    configuring?: () => void;
+    default?: () => void;
+    writing: {
+      [target: string]: () => void;
+    };
+    conflicts?: () => void;
+    install?: () => void;
+    end: () => void;
+  }
+
+  export interface IBase {
+    new(args: string, options: any): IYeomanGenerator;
+    new(args: string[], options: any): IYeomanGenerator;
+    extend(protoProps: IQueueProps, staticProps?: any): IYeomanGenerator;
+  }
+
+  export interface INamedBase {
+    new(args: string, options: any): IYeomanGenerator;
+    new(args: string[], options: any): IYeomanGenerator;
+  }
+
+  export interface IAssert {
+    file(path: string): void;
+    file(paths: string[]): void;
+    fileContent(file: string, reg: RegExp): void;
+
+    /** @param {[String, RegExp][]} pairs */
+    fileContent(pairs: any[][]): void;
+
+    /** @param {[String, RegExp][]|String[]} pairs */
+    files(pairs: any[]): void;
+
+    /**
+     * @param {Object} subject
+     * @param {Object|Array} methods
+     */
+    implement(subject: any, methods: any): void;
+    noFile(file: string): void;
+    noFileContent(file: string, reg: RegExp): void;
+
+    /** @param {[String, RegExp][]} pairs */
+    noFileContent(pairs: any[][]): void;
+
+    /**
+     * @param {Object} subject
+     * @param {Object|Array} methods
+     */
+    noImplement(subject: any, methods: any): void;
+
+    textEqual(value: string, expected: string): void;
+  }
+
+  export interface ITestHelper {
+    createDummyGenerator(): IYeomanGenerator;
+    createGenerator(name: string, dependencies: any[], args: any, options: any): IYeomanGenerator;
+    decorate(context: any, method: string, replacement: Function, options: any): void;
+    gruntfile(options: any, done: Function): void;
+    mockPrompt(generator: IYeomanGenerator, answers: any): void;
+    registerDependencies(dependencies: string[]): void;
+    restore(): void;
+
+    /** @param {String|Function} generator */
+    run(generator: any): IRunContext;
+  }
+
+  export interface IRunContext {
+    async(): Function;
+    inDir(dirPath: string): IRunContext;
+
+    /** @param {String|String[]} args */
+    withArguments(args: any): IRunContext;
+    withGenerators(dependencies: string[]): IRunContext;
+    withOptions(options: any): IRunContext;
+    withPrompts(answers: any): IRunContext;
+  }
+
+  /** @type file file-utils */
+  var file: any;
+  var assert: IAssert;
+  var test: ITestHelper;
+  var generators: {
+    Base: IBase;
+    NamedBase: INamedBase;
+  };
+}
+
+declare module "yeoman-generator" {
+  export = yo;
+}