diff --git a/composer.json b/composer.json
index 727e031..c4bb1e3 100644
--- a/composer.json
+++ b/composer.json
@@ -27,6 +27,7 @@
             ],
             "recurse": false,
             "replace": false,
+            "merge-dev": true,
             "merge-extra": false
         }
     },
@@ -37,7 +38,10 @@
     },
     "scripts": {
         "pre-autoload-dump": "Drupal\\Core\\Composer\\Composer::preAutoloadDump",
-        "post-autoload-dump": "Drupal\\Core\\Composer\\Composer::ensureHtaccess",
+        "post-autoload-dump": [
+          "Drupal\\Core\\Composer\\Composer::ensureHtaccess",
+          "Drupal\\Core\\Composer\\Composer::configurePhpcs"
+        ],
         "post-package-install": "Drupal\\Core\\Composer\\Composer::vendorTestCodeCleanup",
         "post-package-update": "Drupal\\Core\\Composer\\Composer::vendorTestCodeCleanup"
     }
diff --git a/composer.lock b/composer.lock
index e86554f..7d130ed 100644
--- a/composer.lock
+++ b/composer.lock
@@ -4,8 +4,8 @@
         "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#composer-lock-the-lock-file",
         "This file is @generated automatically"
     ],
-    "hash": "7d101b08e5ae002d827cd42ae9a4e344",
-    "content-hash": "60f7057617c6d995bf9946d0b12f0b5d",
+    "hash": "5730b38c5e8cb0c413ccf8faaa695dc9",
+    "content-hash": "3993173afe552cb90686d8dfa7d7f596",
     "packages": [
         {
             "name": "composer/installers",
@@ -2938,6 +2938,42 @@
             "time": "2015-06-14 21:17:01"
         },
         {
+            "name": "drupal/coder",
+            "version": "8.2.7",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/klausi/coder.git",
+                "reference": "a5b5f6b5769393a016da0d106a3b33f932c73331"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/klausi/coder/zipball/a5b5f6b5769393a016da0d106a3b33f932c73331",
+                "reference": "a5b5f6b5769393a016da0d106a3b33f932c73331",
+                "shasum": ""
+            },
+            "require": {
+                "php": ">=5.4.0",
+                "squizlabs/php_codesniffer": ">=2.5.1",
+                "symfony/yaml": ">=2.0.0"
+            },
+            "require-dev": {
+                "phpunit/phpunit": ">=3.7"
+            },
+            "type": "library",
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "GPL-2.0+"
+            ],
+            "description": "Coder is a library to review Drupal code.",
+            "homepage": "https://www.drupal.org/project/coder",
+            "keywords": [
+                "code review",
+                "phpcs",
+                "standards"
+            ],
+            "time": "2016-03-27 09:53:21"
+        },
+        {
             "name": "fabpot/goutte",
             "version": "v3.1.2",
             "source": {
@@ -3999,6 +4035,84 @@
             "time": "2015-06-21 13:59:46"
         },
         {
+            "name": "squizlabs/php_codesniffer",
+            "version": "2.6.1",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/squizlabs/PHP_CodeSniffer.git",
+                "reference": "fb72ed32f8418db5e7770be1653e62e0d6f5dd3d"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/squizlabs/PHP_CodeSniffer/zipball/fb72ed32f8418db5e7770be1653e62e0d6f5dd3d",
+                "reference": "fb72ed32f8418db5e7770be1653e62e0d6f5dd3d",
+                "shasum": ""
+            },
+            "require": {
+                "ext-simplexml": "*",
+                "ext-tokenizer": "*",
+                "ext-xmlwriter": "*",
+                "php": ">=5.1.2"
+            },
+            "require-dev": {
+                "phpunit/phpunit": "~4.0"
+            },
+            "bin": [
+                "scripts/phpcs",
+                "scripts/phpcbf"
+            ],
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "2.x-dev"
+                }
+            },
+            "autoload": {
+                "classmap": [
+                    "CodeSniffer.php",
+                    "CodeSniffer/CLI.php",
+                    "CodeSniffer/Exception.php",
+                    "CodeSniffer/File.php",
+                    "CodeSniffer/Fixer.php",
+                    "CodeSniffer/Report.php",
+                    "CodeSniffer/Reporting.php",
+                    "CodeSniffer/Sniff.php",
+                    "CodeSniffer/Tokens.php",
+                    "CodeSniffer/Reports/",
+                    "CodeSniffer/Tokenizers/",
+                    "CodeSniffer/DocGenerators/",
+                    "CodeSniffer/Standards/AbstractPatternSniff.php",
+                    "CodeSniffer/Standards/AbstractScopeSniff.php",
+                    "CodeSniffer/Standards/AbstractVariableSniff.php",
+                    "CodeSniffer/Standards/IncorrectPatternException.php",
+                    "CodeSniffer/Standards/Generic/Sniffs/",
+                    "CodeSniffer/Standards/MySource/Sniffs/",
+                    "CodeSniffer/Standards/PEAR/Sniffs/",
+                    "CodeSniffer/Standards/PSR1/Sniffs/",
+                    "CodeSniffer/Standards/PSR2/Sniffs/",
+                    "CodeSniffer/Standards/Squiz/Sniffs/",
+                    "CodeSniffer/Standards/Zend/Sniffs/"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "BSD-3-Clause"
+            ],
+            "authors": [
+                {
+                    "name": "Greg Sherwood",
+                    "role": "lead"
+                }
+            ],
+            "description": "PHP_CodeSniffer tokenizes PHP, JavaScript and CSS files and detects violations of a defined set of coding standards.",
+            "homepage": "http://www.squizlabs.com/php-codesniffer",
+            "keywords": [
+                "phpcs",
+                "standards"
+            ],
+            "time": "2016-05-30 22:24:32"
+        },
+        {
             "name": "symfony/browser-kit",
             "version": "v2.7.6",
             "source": {
diff --git a/core/composer.json b/core/composer.json
index ddcd1ce..2efa374 100644
--- a/core/composer.json
+++ b/core/composer.json
@@ -36,10 +36,12 @@
     "require-dev": {
         "behat/mink": "~1.7",
         "behat/mink-goutte-driver": "~1.2",
+        "drupal/coder": "~8.2",
         "jcalderonzumba/gastonjs": "~1.0.2",
         "jcalderonzumba/mink-phantomjs-driver": "~0.3.1",
         "mikey179/vfsStream": "~1.2",
         "phpunit/phpunit": "~4.8",
+        "squizlabs/php_codesniffer": "~2",
         "symfony/css-selector": "~2.8"
     },
     "replace": {
@@ -157,6 +159,9 @@
     },
     "scripts": {
         "pre-autoload-dump": "Drupal\\Core\\Composer\\Composer::preAutoloadDump",
-        "post-autoload-dump": "Drupal\\Core\\Composer\\Composer::ensureHtaccess"
+        "post-autoload-dump": [
+          "Drupal\\Core\\Composer\\Composer::ensureHtaccess",
+          "Drupal\\Core\\Composer\\Composer::configurePhpcs"
+        ]
     }
 }
diff --git a/core/lib/Drupal/Core/Composer/Composer.php b/core/lib/Drupal/Core/Composer/Composer.php
index 51a4917..2954d16 100644
--- a/core/lib/Drupal/Core/Composer/Composer.php
+++ b/core/lib/Drupal/Core/Composer/Composer.php
@@ -136,6 +136,31 @@ public static function ensureHtaccess(Event $event) {
   }
 
   /**
+   * Configures phpcs if present.
+   *
+   * @param \Composer\Script\Event $event
+   */
+  public static function configurePhpcs(Event $event) {
+    // Grab the local repo which tells us what's been installed.
+    $local_repository = $event->getComposer()
+      ->getRepositoryManager()
+      ->getLocalRepository();
+    // Make sure both phpcs and coder are installed.
+    $phpcs_package = $local_repository->findPackage('squizlabs/php_codesniffer', '*');
+    $coder_package = $local_repository->findPackage('drupal/coder', '*');
+    if (!empty($phpcs_package) && !empty($coder_package)) {
+      // Set phpcs' installed_paths config to point to our coder_sniffer
+      // directory.
+      $config = $event->getComposer()->getConfig();
+      $bin_dir = $config->get('bin-dir');
+      $vendor_dir = $config->get('vendor-dir');
+      $command = $bin_dir . '/phpcs --config-set installed_paths ' .
+        $vendor_dir . '/drupal/coder/coder_sniffer';
+      exec($command);
+    }
+  }
+
+  /**
    * Remove possibly problematic test files from vendored projects.
    *
    * @param \Composer\Installer\PackageEvent $event