diff --git a/.editorconfig b/.editorconfig
new file mode 100644
index 00000000..653a04c7
--- /dev/null
+++ b/.editorconfig
@@ -0,0 +1,13 @@
+; top-most EditorConfig file
+root = true
+
+; Unix-style newlines
+[*]
+charset = utf-8
+end_of_line = LF
+insert_final_newline = true
+trim_trailing_whitespace = true
+
+[*.{php,json,yaml}]
+indent_style = space
+indent_size = 4
diff --git a/.gitattributes b/.gitattributes
new file mode 100644
index 00000000..de0330e2
--- /dev/null
+++ b/.gitattributes
@@ -0,0 +1,12 @@
+/.* export-ignore
+/tools/ export-ignore
+/phpstan*.neon export-ignore
+/phpunit.xml.dist export-ignore
+/psalm*.xml export-ignore
+/tests/ export-ignore
+
+*       text=auto eol=lf
+*.json  text whitespace=blank-at-eol,blank-at-eof,space-before-tab,tab-in-indent,tabwidth=4
+*.md    text whitespace=blank-at-eol,blank-at-eof
+*.php   text whitespace=blank-at-eol,blank-at-eof,space-before-tab,tab-in-indent,tabwidth=4 diff=php
+*.yml   text whitespace=blank-at-eol,blank-at-eof,space-before-tab,tab-in-indent,tabwidth=4
diff --git a/.php-cs-fixer.dist.php b/.php-cs-fixer.dist.php
index d4bd85e1..1be9a568 100644
--- a/.php-cs-fixer.dist.php
+++ b/.php-cs-fixer.dist.php
@@ -1,17 +1,23 @@
 <?php
 
+use OpenApi\Tools\CSFixer\LicenseFixer;
+
 $finder = PhpCsFixer\Finder::create()
     ->path('src')->name('*.php')
     ->path('tests')->name('*.php')
     ->path('Examples')->name('*.php')
-    //->exclude('tests/Fixtures')
+    ->path('tools')->name('*.php')
     ->in(__DIR__)
 ;
 
 return (new PhpCsFixer\Config())
+    ->registerCustomFixers([
+        new LicenseFixer(),
+    ])
     ->setRules([
         '@PSR2' => true,
         '@DoctrineAnnotation' => true,
+        'OpenApi/license' => true,
         'array_syntax' => ['syntax' => 'short'],
         'no_unused_imports' => true,
         'blank_line_before_statement' => ['statements' => ['return']],
diff --git a/composer.json b/composer.json
index 2fa76fc9..ce82aa05 100644
--- a/composer.json
+++ b/composer.json
@@ -1,112 +1,113 @@
 {
-  "name": "zircote/swagger-php",
-  "type": "library",
-  "license": "Apache-2.0",
-  "bin": [
-    "bin/openapi"
-  ],
-  "description": "swagger-php - Generate interactive documentation for your RESTful API using phpdoc annotations",
-  "keywords": [
-    "json",
-    "rest",
-    "api",
-    "service discovery"
-  ],
-  "homepage": "https://github.com/zircote/swagger-php/",
-  "authors": [
-    {
-      "name": "Robert Allen",
-      "email": "zircote@gmail.com"
+    "name": "zircote/swagger-php",
+    "type": "library",
+    "license": "Apache-2.0",
+    "bin": [
+        "bin/openapi"
+    ],
+    "description": "swagger-php - Generate interactive documentation for your RESTful API using phpdoc annotations",
+    "keywords": [
+        "json",
+        "rest",
+        "api",
+        "service discovery"
+    ],
+    "homepage": "https://github.com/zircote/swagger-php/",
+    "authors": [
+        {
+            "name": "Robert Allen",
+            "email": "zircote@gmail.com"
+        },
+        {
+            "name": "Bob Fanger",
+            "email": "bfanger@gmail.com",
+            "homepage": "https://bfanger.nl"
+        },
+        {
+            "name": "Martin Rademacher",
+            "email": "mano@radebatz.net",
+            "homepage": "https://radebatz.net"
+        }
+    ],
+    "config": {
+        "bin-dir": "bin",
+        "optimize-autoloader": true,
+        "sort-packages": true,
+        "allow-plugins": {
+            "composer/package-versions-deprecated": true
+        }
     },
-    {
-      "name": "Bob Fanger",
-      "email": "bfanger@gmail.com",
-      "homepage": "https://bfanger.nl"
+    "minimum-stability": "stable",
+    "extra": {
+        "branch-alias": {
+            "dev-master": "4.x-dev"
+        }
     },
-    {
-      "name": "Martin Rademacher",
-      "email": "mano@radebatz.net",
-      "homepage": "https://radebatz.net"
+    "require": {
+        "php": ">=7.2",
+        "ext-json": "*",
+        "doctrine/annotations": "^1.7",
+        "psr/log": "^1.1 || ^2.0 || 3.0",
+        "symfony/finder": ">=2.2",
+        "symfony/yaml": ">=3.3"
+    },
+    "autoload": {
+        "psr-4": {
+            "OpenApi\\": "src"
+        }
+    },
+    "require-dev": {
+        "composer/package-versions-deprecated": "^1.11",
+        "friendsofphp/php-cs-fixer": "^2.17 || ^3.0",
+        "phpstan/phpstan": "^1.6",
+        "phpunit/phpunit": ">=8",
+        "vimeo/psalm": "^4.23"
+    },
+    "autoload-dev": {
+        "exclude-from-classmap": [
+            "/tests/Fixtures"
+        ],
+        "psr-4": {
+            "OpenApi\\Tools\\": "tools/src/",
+            "OpenApi\\Tests\\": "tests/",
+            "AnotherNamespace\\": "tests/Fixtures/AnotherNamespace",
+            "OpenApi\\Tests\\Fixtures\\Annotations\\": "tests/Fixtures/Annotations"
+        }
+    },
+    "scripts-descriptions": {
+        "cs": "Fix all codestyle issues",
+        "lint": "Test codestyle",
+        "test": "Run all non-legacy and codestyle tests",
+        "testlegacy": "Run tests using the legacy TokenAnalyser",
+        "testall": "Run all tests (test + testlegacy)",
+        "analyse": "Run static analysis (phpstan/psalm)",
+        "spectral": "Run spectral lint over all .yaml files in the Examples folder",
+        "docs:refgen": "Rebuild the annotations/attributes reference markup files",
+        "docs:dev": "Run dev server for local development of gh-pages",
+        "docs:build": "Re-build static gh-pages"
+    },
+    "scripts": {
+        "cs": "php-cs-fixer fix --allow-risky=yes",
+        "lint": "@cs --dry-run",
+        "test": [
+            "phpunit",
+            "@lint"
+        ],
+        "testlegacy": "export PHPUNIT_ANALYSER=legacy && phpunit",
+        "testall": [
+            "@test",
+            "@testlegacy"
+        ],
+        "analyse": [
+            "phpstan analyse --memory-limit=2G",
+            "psalm"
+        ],
+        "spectral": "for ff in `find Examples -name '*.yaml'`; do spectral lint $ff; done",
+        "docs:refgen": "php tools/refgen.php",
+        "docs:dev": "cd docs && npm run dev",
+        "docs:build": [
+            "@docs:refgen",
+            "cd docs && npm run build"
+        ]
     }
-  ],
-  "config": {
-    "bin-dir": "bin",
-    "optimize-autoloader": true,
-    "sort-packages": true,
-    "allow-plugins": {
-      "composer/package-versions-deprecated": true
-    }
-  },
-  "minimum-stability": "stable",
-  "extra": {
-    "branch-alias": {
-      "dev-master": "4.x-dev"
-    }
-  },
-  "require": {
-    "php": ">=7.2",
-    "ext-json": "*",
-    "doctrine/annotations": "^1.7",
-    "psr/log": "^1.1 || ^2.0 || 3.0",
-    "symfony/finder": ">=2.2",
-    "symfony/yaml": ">=3.3"
-  },
-  "autoload": {
-    "psr-4": {
-      "OpenApi\\": "src"
-    }
-  },
-  "require-dev": {
-    "composer/package-versions-deprecated": "^1.11",
-    "friendsofphp/php-cs-fixer": "^2.17 || ^3.0",
-    "phpstan/phpstan": "^1.6",
-    "phpunit/phpunit": ">=8",
-    "vimeo/psalm": "^4.23"
-  },
-  "autoload-dev": {
-    "exclude-from-classmap": [
-      "/tests/Fixtures"
-    ],
-    "psr-4": {
-      "OpenApi\\Tests\\": "tests/",
-      "AnotherNamespace\\": "tests/Fixtures/AnotherNamespace",
-      "OpenApi\\Tests\\Fixtures\\Annotations\\": "tests/Fixtures/Annotations"
-    }
-  },
-  "scripts-descriptions": {
-    "cs": "Fix all codestyle issues",
-    "lint": "Test codestyle",
-    "test": "Run all non-legacy and codestyle tests",
-    "testlegacy": "Run tests using the legacy TokenAnalyser",
-    "testall": "Run all tests (test + testlegacy)",
-    "analyse": "Run static analysis (phpstan/psalm)",
-    "spectral": "Run spectral lint over all .yaml files in the Examples folder",
-    "docs:refgen": "Rebuild the annotations/attributes reference markup files",
-    "docs:dev": "Run dev server for local development of gh-pages",
-    "docs:build": "Re-build static gh-pages"
-  },
-  "scripts": {
-    "cs": "php-cs-fixer fix --allow-risky=yes",
-    "lint": "@cs --dry-run",
-    "test": [
-      "phpunit",
-      "@lint"
-    ],
-    "testlegacy": "export PHPUNIT_ANALYSER=legacy && phpunit",
-    "testall": [
-      "@test",
-      "@testlegacy"
-    ],
-    "analyse": [
-      "phpstan analyse --memory-limit=2G",
-      "psalm"
-    ],
-    "spectral": "for ff in `find Examples -name '*.yaml'`; do spectral lint $ff; done",
-    "docs:refgen": "php docs/refgen.php",
-    "docs:dev": "cd docs && npm run dev",
-    "docs:build": [
-      "@docs:refgen",
-      "cd docs && npm run build"
-    ]
-  }
 }
diff --git a/src/Processors/CleanUnusedComponents.php b/src/Processors/CleanUnusedComponents.php
index bd90ae22..adadf1b5 100644
--- a/src/Processors/CleanUnusedComponents.php
+++ b/src/Processors/CleanUnusedComponents.php
@@ -1,5 +1,9 @@
 <?php declare(strict_types=1);
 
+/**
+ * @license Apache 2.0
+ */
+
 namespace OpenApi\Processors;
 
 use OpenApi\Analysis;
diff --git a/src/Processors/DocblockTrait.php b/src/Processors/DocblockTrait.php
index 7ad0a730..a6f1bfb6 100644
--- a/src/Processors/DocblockTrait.php
+++ b/src/Processors/DocblockTrait.php
@@ -1,5 +1,9 @@
 <?php
 
+/**
+ * @license Apache 2.0
+ */
+
 namespace OpenApi\Processors;
 
 use OpenApi\Annotations\AbstractAnnotation;
diff --git a/tools/refgen.php b/tools/refgen.php
new file mode 100644
index 00000000..faa8be59
--- /dev/null
+++ b/tools/refgen.php
@@ -0,0 +1,20 @@
+<?php declare(strict_types=1);
+
+require_once __DIR__ . '/../vendor/autoload.php';
+
+use OpenApi\Tools\Docs\RefGenerator;
+
+$refgen = new RefGenerator(__DIR__ . '/../');
+
+foreach ($refgen->types() as $type) {
+    ob_start();
+
+    echo $refgen->preamble($type);
+    foreach ($refgen->classesForType($type) as $name => $details) {
+        echo $refgen->formatHeader($name, $type);
+        $method = "format{$type}Details";
+        echo $refgen->$method($name, $details['fqdn'], $details['filename']);
+    }
+
+    file_put_contents($refgen->docPath('reference/' . strtolower($type) . '.md'), ob_get_clean());
+}
diff --git a/tools/src/CSFixer/AbstractFixer.php b/tools/src/CSFixer/AbstractFixer.php
new file mode 100644
index 00000000..88bae613
--- /dev/null
+++ b/tools/src/CSFixer/AbstractFixer.php
@@ -0,0 +1,28 @@
+<?php declare(strict_types=1);
+
+/**
+ * @license Apache 2.0
+ */
+
+namespace OpenApi\Tools\CSFixer;
+
+use PhpCsFixer\Fixer\FixerInterface;
+use PhpCsFixer\Tokenizer\Tokens;
+
+abstract class AbstractFixer implements FixerInterface
+{
+    public function isCandidate(Tokens $tokens): bool
+    {
+        return true;
+    }
+
+    public function isRisky(): bool
+    {
+        return false;
+    }
+
+    public function supports(\SplFileInfo $file): bool
+    {
+        return $file->getExtension() == 'php';
+    }
+}
diff --git a/tools/src/CSFixer/LicenseFixer.php b/tools/src/CSFixer/LicenseFixer.php
new file mode 100644
index 00000000..a9c83448
--- /dev/null
+++ b/tools/src/CSFixer/LicenseFixer.php
@@ -0,0 +1,63 @@
+<?php declare(strict_types=1);
+
+/**
+ * @license Apache 2.0
+ */
+
+namespace OpenApi\Tools\CSFixer;
+
+use PhpCsFixer\FixerDefinition\FixerDefinition;
+use PhpCsFixer\FixerDefinition\FixerDefinitionInterface;
+use PhpCsFixer\Tokenizer\Token;
+use PhpCsFixer\Tokenizer\Tokens;
+
+class LicenseFixer extends AbstractFixer
+{
+    public function fix(\SplFileInfo $file, Tokens $tokens): void
+    {
+        foreach ($tokens as $index => $token) {
+            if ($token->isComment()) {
+                if (false !== strpos($token->getContent(), '@license')) {
+                    return;
+                }
+            }
+        }
+
+        $license = <<< EOC
+/**
+ * @license Apache 2.0
+ */
+EOC;
+
+        if ($sequence = $tokens->findSequence([[T_NAMESPACE]])) {
+            $index = array_keys($sequence)[0];
+            $tokens->insertAt($index, new Token([
+                T_COMMENT,
+                $license,
+            ]));
+        }
+    }
+
+    public function getDefinition(): FixerDefinitionInterface
+    {
+        return new FixerDefinition(
+            'All .php files MUST have a @license docblock annotation before namespace / use statement(s)',
+            []
+        );
+    }
+
+    public function getName(): string
+    {
+        return 'OpenApi/license';
+    }
+
+    public function getPriority(): int
+    {
+        return 5;
+    }
+
+    public function supports(\SplFileInfo $file): bool
+    {
+        return parent::supports($file) && false !== strpos($file->getPath(), '/src/');
+    }
+}
diff --git a/docs/refgen.php b/tools/src/Docs/RefGenerator.php
similarity index 87%
rename from docs/refgen.php
rename to tools/src/Docs/RefGenerator.php
index 5ef6324a..99f62a52 100644
--- a/docs/refgen.php
+++ b/tools/src/Docs/RefGenerator.php
@@ -1,10 +1,14 @@
 <?php declare(strict_types=1);
 
+/**
+ * @license Apache 2.0
+ */
+
+namespace OpenApi\Tools\Docs;
+
 use OpenApi\Analysers\TokenScanner;
 use OpenApi\Annotations\AbstractAnnotation;
 
-require_once __DIR__ . '/../vendor/autoload.php';
-
 class RefGenerator
 {
     const ATTRIBUTES = 'Attributes';
@@ -12,15 +16,19 @@ class RefGenerator
     const NO_DETAILS_AVAILABLE = 'No details available.';
 
     protected $scanner;
+    protected $projectRoot;
 
-    public function __construct()
+    public function __construct($projectRoot)
     {
         $this->scanner = new TokenScanner();
+        $this->projectRoot = realpath($projectRoot);
+    }
+
+    public function docPath(string $relativeName): string
+    {
+        return $this->projectRoot . '/docs/' . $relativeName;
     }
 
-    /**
-     *
-     */
     public function preamble(string $type): string
     {
         return <<< EOT
@@ -37,13 +45,10 @@ In addition to this page, there are also a number of [examples](https://github.c
 EOT;
     }
 
-    /**
-     *
-     */
     public function classesForType(string $type): array
     {
         $classes = [];
-        $dir = new DirectoryIterator(__DIR__ . '/../src/' . $type);
+        $dir = new \DirectoryIterator($this->projectRoot . '/src/' . $type);
         foreach ($dir as $entry) {
             if (!$entry->isFile() || $entry->getExtension() != 'php') {
                 continue;
@@ -63,17 +68,11 @@ EOT;
         return $classes;
     }
 
-    /**
-     *
-     */
     public function types(): array
     {
         return [self::ANNOTATIONS, self::ATTRIBUTES];
     }
 
-    /**
-     *
-     */
     public function formatHeader(string $name, string $type): string
     {
         return <<< EOT
@@ -83,16 +82,13 @@ EOT;
 EOT;
     }
 
-    /**
-     *
-     */
     public function formatAttributesDetails(string $name, string $fqdn, string $filename): string
     {
-        $rctor = (new ReflectionClass($fqdn))->getMethod('__construct');
+        $rctor = (new \ReflectionClass($fqdn))->getMethod('__construct');
 
         ob_start();
 
-        $rc = new ReflectionClass($fqdn);
+        $rc = new \ReflectionClass($fqdn);
         $classDocumentation = $this->extractDocumentation($rc->getDocComment());
         echo $classDocumentation['content'] . PHP_EOL;
 
@@ -104,7 +100,7 @@ EOT;
         $parameters = $rctor->getParameters();
         if ($parameters) {
             echo PHP_EOL . '#### Parameters' . PHP_EOL;
-            echo '---'.PHP_EOL;
+            echo '---' . PHP_EOL;
 
             echo '<dl>' . PHP_EOL;
             foreach ($parameters as $rp) {
@@ -127,7 +123,7 @@ EOT;
 
         if ($classDocumentation['see']) {
             echo PHP_EOL . '#### Reference' . PHP_EOL;
-            echo '---'.PHP_EOL;
+            echo '---' . PHP_EOL;
 
             foreach ($classDocumentation['see'] as $link) {
                 echo '- ' . $link . PHP_EOL;
@@ -148,7 +144,7 @@ EOT;
 
         ob_start();
 
-        $rc = new ReflectionClass($fqdn);
+        $rc = new \ReflectionClass($fqdn);
         $classDocumentation = $this->extractDocumentation($rc->getDocComment());
         echo $classDocumentation['content'] . PHP_EOL;
 
@@ -161,11 +157,11 @@ EOT;
 
         if ($properties) {
             echo PHP_EOL . '#### Properties' . PHP_EOL;
-            echo '---'.PHP_EOL;
+            echo '---' . PHP_EOL;
 
             echo '<dl>' . PHP_EOL;
             foreach ($properties as $property) {
-                $rp = new ReflectionProperty($fqdn, $property);
+                $rp = new \ReflectionProperty($fqdn, $property);
                 $propertyDocumentation = $this->extractDocumentation($rp->getDocComment());
                 if ($var = $this->getReflectionType($fqdn, $rp, false, $propertyDocumentation['var'])) {
                     $var = ' : <span style="font-family: monospace;">' . $var . '</span>';
@@ -193,7 +189,7 @@ EOT;
 
         if ($classDocumentation['see']) {
             echo PHP_EOL . '#### Reference' . PHP_EOL;
-            echo '---'.PHP_EOL;
+            echo '---' . PHP_EOL;
 
             foreach ($classDocumentation['see'] as $link) {
                 echo '- ' . $link . PHP_EOL;
@@ -212,7 +208,7 @@ EOT;
     {
         $props = [];
         foreach ($fqdn::$_nested as $details) {
-            $props[] = ((array)$details)[0];
+            $props[] = ((array) $details)[0];
         }
 
         return $props;
@@ -225,10 +221,11 @@ EOT;
     {
         if ($fqdn::$_parents) {
             echo PHP_EOL . '#### Allowed in' . PHP_EOL;
-            echo '---'.PHP_EOL;
+            echo '---' . PHP_EOL;
 
             $parents = array_map(function (string $parent) {
                 $shortName = $this->shortName($parent);
+
                 return '<a href="#' . strtolower($shortName) . '">' . $shortName . '</a>';
             }, $fqdn::$_parents);
             echo implode(', ', $parents) . PHP_EOL;
@@ -236,10 +233,11 @@ EOT;
 
         if ($fqdn::$_nested) {
             echo PHP_EOL . '#### Nested elements' . PHP_EOL;
-            echo '---'.PHP_EOL;
+            echo '---' . PHP_EOL;
 
             $nested = array_map(function (string $nested) {
                 $shortName = $this->shortName($nested);
+
                 return '<a href="#' . strtolower($shortName) . '">' . $shortName . '</a>';
             }, array_keys($fqdn::$_nested));
             echo implode(', ', $nested) . PHP_EOL;
@@ -263,7 +261,7 @@ EOT;
         $var = [];
 
         if ($type = $rp->getType()) {
-            if ($type instanceof ReflectionUnionType) {
+            if ($type instanceof \ReflectionUnionType) {
                 foreach ($type->getTypes() as $type) {
                     $var[] = $type->getName();
                 }
@@ -292,7 +290,7 @@ EOT;
             return ['content' => '', 'see' => [], 'var' => '', 'params' => []];
         }
 
-        $comment = preg_split('/(\n|\r\n)/', (string)$docblock);
+        $comment = preg_split('/(\n|\r\n)/', (string) $docblock);
 
         $comment[0] = preg_replace('/[ \t]*\\/\*\*/', '', $comment[0]); // strip '/**'
         $i = count($comment) - 1;
@@ -334,20 +332,3 @@ EOT;
         return ['content' => $content, 'see' => $see, 'var' => $var, 'params' => $params];
     }
 }
-
-
-// ================================================================================
-$refgen = new RefGenerator();
-
-foreach ($refgen->types() as $type) {
-    ob_start();
-
-    echo $refgen->preamble($type);
-    foreach ($refgen->classesForType($type) as $name => $details) {
-        echo $refgen->formatHeader($name, $type);
-        $method = "format{$type}Details";
-        echo $refgen->$method($name, $details['fqdn'], $details['filename']);
-    }
-
-    file_put_contents(__DIR__ . '/reference/' . strtolower($type) . '.md', ob_get_clean());
-}