diff --git a/src/Builder.php b/src/Builder.php
index 9c42b46..94a0802 100644
--- a/src/Builder.php
+++ b/src/Builder.php
@@ -4,12 +4,21 @@ namespace Opdavies\GmailFilterBuilder;
 
 class Builder
 {
+    /**
+     * @var array
+     */
     private $filters = [];
 
-    public function __construct(array $filters) {
+    public function __construct(array $filters)
+    {
         $this->filters = $filters;
     }
 
+    /**
+     * Build XML for a set of filters.
+     *
+     * @return string
+     */
     public function build()
     {
         $prefix = "<?xml version='1.0' encoding='UTF-8'?><feed xmlns='http://www.w3.org/2005/Atom' xmlns:apps='http://schemas.google.com/apps/2006'>";
@@ -23,6 +32,8 @@ class Builder
     }
 
     /**
+     * Build XML for an entry.
+     *
      * @param array $items
      *
      * @return string
diff --git a/src/Filter.php b/src/Filter.php
index 05d1bff..61ac922 100644
--- a/src/Filter.php
+++ b/src/Filter.php
@@ -4,8 +4,16 @@ namespace Opdavies\GmailFilterBuilder;
 
 class Filter
 {
+    /**
+     * @var array
+     */
     private $properties = [];
 
+    /**
+     * @param string $value
+     *
+     * @return $this
+     */
     public function has($value)
     {
         $this->properties['hasTheWord'] = $value;
@@ -13,6 +21,11 @@ class Filter
         return $this;
     }
 
+    /**
+     * @param string $value
+     *
+     * @return $this
+     */
     public function hasNot($value)
     {
         $this->properties['doesNotHaveTheWord'] = $value;
@@ -20,26 +33,39 @@ class Filter
         return $this;
     }
 
+    /**
+     * @param string|array $values
+     *
+     * @return $this
+     */
     public function from($values)
     {
-        $this->properties['from'] = collect($values)
-            ->map(function ($value) {
-                return trim($value);
-            })->all();
+        $this->properties['from'] = collect($values)->map(function ($value) {
+            return trim($value);
+        })->all();
 
         return $this;
     }
 
+    /**
+     * @param string|array $values
+     *
+     * @return $this
+     */
     public function to($values)
     {
-        $this->properties['to'] = collect($values)
-            ->map(function ($value) {
-                return trim($value);
-            })->all();
+        $this->properties['to'] = collect($values)->map(function ($value) {
+            return trim($value);
+        })->all();
 
         return $this;
     }
 
+    /**
+     * @param string $subject
+     *
+     * @return $this
+     */
     public function subject($subject)
     {
         $this->properties['subject'] = $subject;
@@ -47,6 +73,9 @@ class Filter
         return $this;
     }
 
+    /**
+     * @return $this
+     */
     public function hasAttachment()
     {
         $this->properties['hasAttachment'] = 'true';
@@ -54,6 +83,9 @@ class Filter
         return $this;
     }
 
+    /**
+     * @return $this
+     */
     public function excludeChats()
     {
         $this->properties['excludeChats'] = 'true';
@@ -61,6 +93,11 @@ class Filter
         return $this;
     }
 
+    /**
+     * @param string $label
+     *
+     * @return $this
+     */
     public function label($label)
     {
         $this->properties['label'] = $label;
@@ -68,6 +105,9 @@ class Filter
         return $this;
     }
 
+    /**
+     * @return $this
+     */
     public function archive()
     {
         $this->properties['shouldArchive'] = 'true';
@@ -75,6 +115,11 @@ class Filter
         return $this;
     }
 
+    /**
+     * @param string $label
+     *
+     * @return $this
+     */
     public function labelAndArchive($label)
     {
         $this->label($label)->archive();
@@ -82,6 +127,9 @@ class Filter
         return $this;
     }
 
+    /**
+     * @return $this
+     */
     public function spam()
     {
         $this->properties['shouldSpam'] = 'true';
@@ -90,6 +138,9 @@ class Filter
         return $this;
     }
 
+    /**
+     * @return $this
+     */
     public function neverSpam()
     {
         $this->properties['shouldSpam'] = 'false';
@@ -98,6 +149,9 @@ class Filter
         return $this;
     }
 
+    /**
+     * @return $this
+     */
     public function trash()
     {
         $this->properties['shouldTrash'] = 'true';
@@ -105,6 +159,9 @@ class Filter
         return $this;
     }
 
+    /**
+     * @return $this
+     */
     public function read()
     {
         $this->properties['markAsRead'] = 'true';
@@ -112,6 +169,9 @@ class Filter
         return $this;
     }
 
+    /**
+     * @return $this
+     */
     public function star()
     {
         $this->properties['shouldStar'] = 'true';
@@ -119,6 +179,11 @@ class Filter
         return $this;
     }
 
+    /**
+     * @param string $to
+     *
+     * @return $this
+     */
     public function forward($to)
     {
         $this->properties['forwardTo'] = $to;
@@ -126,6 +191,9 @@ class Filter
         return $this;
     }
 
+    /**
+     * @return $this
+     */
     public function important()
     {
         $this->properties['shouldAlwaysMarkAsImportant'] = 'true';
@@ -133,6 +201,9 @@ class Filter
         return $this;
     }
 
+    /**
+     * @return $this
+     */
     public function notImportant()
     {
         $this->properties['shouldNeverMarkAsImportant'] = 'true';
@@ -140,6 +211,11 @@ class Filter
         return $this;
     }
 
+    /**
+     * @param string $category
+     *
+     * @return $this
+     */
     public function categorise($category)
     {
         $this->properties['smartLabelToApply'] = $category;
@@ -147,6 +223,9 @@ class Filter
         return $this;
     }
 
+    /**
+     * @return array
+     */
     public function getProperties()
     {
         return $this->properties;
diff --git a/tests/Unit/FilterTest.php b/tests/Unit/FilterTest.php
index 0212d46..8f9c425 100644
--- a/tests/Unit/FilterTest.php
+++ b/tests/Unit/FilterTest.php
@@ -55,8 +55,7 @@ class FilterTest extends TestCase
         // Ensure that we can set multiple from addresses.
         $this->assertEquals(
             ['from' => ['foo@example.com', 'bar@example.com']],
-            $this->filter->from(['foo@example.com', 'bar@example.com'])
-                ->getProperties()
+            $this->filter->from(['foo@example.com', 'bar@example.com'])->getProperties()
         );
     }
 
@@ -72,8 +71,7 @@ class FilterTest extends TestCase
 
         $this->assertEquals(
             ['to' => ['bar@example.com', 'baz@example.com']],
-            $this->filter->to(['bar@example.com', 'baz@example.com'])
-                ->getProperties()
+            $this->filter->to(['bar@example.com', 'baz@example.com'])->getProperties()
         );
     }