diff --git a/tests/UnifiedSpecTests/Constraint/Matches.php b/tests/UnifiedSpecTests/Constraint/Matches.php
index e1b659a3e..b793614a4 100644
--- a/tests/UnifiedSpecTests/Constraint/Matches.php
+++ b/tests/UnifiedSpecTests/Constraint/Matches.php
@@ -3,6 +3,7 @@
 namespace MongoDB\Tests\UnifiedSpecTests\Constraint;
 
 use LogicException;
+use MongoDB\BSON\Document;
 use MongoDB\BSON\Serializable;
 use MongoDB\BSON\Type;
 use MongoDB\Model\BSONArray;
@@ -25,10 +26,13 @@
 use function is_int;
 use function is_object;
 use function ltrim;
+use function PHPUnit\Framework\assertInstanceOf;
 use function PHPUnit\Framework\assertIsBool;
 use function PHPUnit\Framework\assertIsString;
+use function PHPUnit\Framework\assertJson;
 use function PHPUnit\Framework\assertMatchesRegularExpression;
 use function PHPUnit\Framework\assertNotNull;
+use function PHPUnit\Framework\assertStringStartsWith;
 use function PHPUnit\Framework\assertThat;
 use function PHPUnit\Framework\containsOnly;
 use function PHPUnit\Framework\isInstanceOf;
@@ -39,6 +43,7 @@
 use function sprintf;
 use function str_starts_with;
 use function strrchr;
+use function trim;
 
 /**
  * Constraint that checks if one value matches another.
@@ -263,6 +268,35 @@ private function assertMatchesOperator(BSONDocument $operator, $actual, string $
             return;
         }
 
+        if ($name === '$$matchAsDocument') {
+            assertInstanceOf(BSONDocument::class, $operator['$$matchAsDocument'], '$$matchAsDocument requires a BSON document');
+            assertIsString($actual, '$$matchAsDocument requires actual value to be a JSON string');
+            assertJson($actual, '$$matchAsDocument requires actual value to be a JSON string');
+
+            /* Note: assertJson() accepts array and scalar values, but the spec
+             * assumes that the JSON string will yield a document. */
+            assertStringStartsWith('{', trim($actual), '$$matchAsDocument requires actual value to be a JSON string denoting an object');
+
+            $actualDocument = Document::fromJSON($actual)->toPHP();
+            $constraint = new Matches($operator['$$matchAsDocument'], $this->entityMap, allowExtraRootKeys: false);
+
+            if (! $constraint->evaluate($actualDocument, '', true)) {
+                self::failAt(sprintf('%s did not match: %s', (new Exporter())->shortenedExport($actual), $constraint->additionalFailureDescription(null)), $keyPath);
+            }
+
+            return;
+        }
+
+        if ($name === '$$matchAsRoot') {
+            $constraint = new Matches($operator['$$matchAsRoot'], $this->entityMap, allowExtraRootKeys: true);
+
+            if (! $constraint->evaluate($actual, '', true)) {
+                self::failAt(sprintf('$actual did not match as root-level document: %s', $constraint->additionalFailureDescription(null)), $keyPath);
+            }
+
+            return;
+        }
+
         if ($name === '$$matchesEntity') {
             assertNotNull($this->entityMap, '$$matchesEntity requires EntityMap');
             assertIsString($operator['$$matchesEntity'], '$$matchesEntity requires string');
diff --git a/tests/UnifiedSpecTests/Constraint/MatchesTest.php b/tests/UnifiedSpecTests/Constraint/MatchesTest.php
index 0de7aa9cb..41b57fad1 100644
--- a/tests/UnifiedSpecTests/Constraint/MatchesTest.php
+++ b/tests/UnifiedSpecTests/Constraint/MatchesTest.php
@@ -30,6 +30,12 @@ public function testFlexibleNumericComparison(): void
         $this->assertResult(true, $c, ['x' => 1.0, 'y' => 1.0], 'Float instead of expected int matches');
         $this->assertResult(true, $c, ['x' => 1, 'y' => 1], 'Int instead of expected float matches');
         $this->assertResult(false, $c, ['x' => 'foo', 'y' => 1.0], 'Different type does not match');
+
+        /* Matches uses PHPUnit's comparators, which follow PHP behavior. This
+         * is more liberal than the comparison logic called for by the unified
+         * test format. This test can be removed when PHPLIB-1577 is addressed.
+         */
+        $this->assertResult(true, $c, ['x' => '1.0', 'y' => '1'], 'Numeric strings may match ints and floats');
     }
 
     public function testDoNotAllowExtraRootKeys(): void
@@ -171,6 +177,37 @@ public function testOperatorSessionLsid(): void
         $this->assertResult(false, $c, ['x' => 1], 'session LSID does not match (embedded)');
     }
 
+    public function testOperatorMatchAsDocument(): void
+    {
+        $c = new Matches(['json' => ['$$matchAsDocument' => ['x' => 1]]]);
+        $this->assertResult(true, $c, ['json' => '{"x": 1}'], 'JSON document matches');
+        $this->assertResult(false, $c, ['json' => '{"x": 2}'], 'JSON document does not match');
+        $this->assertResult(false, $c, ['json' => '{"x": 1, "y": 2}'], 'JSON document cannot contain extra fields');
+
+        $c = new Matches(['json' => ['$$matchAsDocument' => ['x' => 1.0]]]);
+        $this->assertResult(true, $c, ['json' => '{"x": 1}'], 'JSON document matches (flexible numeric comparison)');
+
+        $c = new Matches(['json' => ['$$matchAsDocument' => ['x' => ['$$exists' => true]]]]);
+        $this->assertResult(true, $c, ['json' => '{"x": 1}'], 'JSON document matches (special operators)');
+        $this->assertResult(false, $c, ['json' => '{"y": 1}'], 'JSON document does not match (special operators)');
+
+        $c = new Matches(['json' => ['$$matchAsDocument' => ['x' => ['$$type' => 'objectId']]]]);
+        $this->assertResult(true, $c, ['json' => '{"x": {"$oid": "57e193d7a9cc81b4027498b5"}}'], 'JSON document matches (extended JSON)');
+        $this->assertResult(false, $c, ['json' => '{"x": {"$numberDecimal": "1234.5"}}'], 'JSON document does not match (extended JSON)');
+    }
+
+    public function testOperatorMatchAsRoot(): void
+    {
+        $c = new Matches(['x' => ['$$matchAsRoot' => ['y' => 2]]]);
+        $this->assertResult(true, $c, ['x' => ['y' => 2, 'z' => 3]], 'Nested document matches (allow extra fields)');
+        $this->assertResult(true, $c, ['x' => ['y' => 2.0, 'z' => 3.0]], 'Nested document matches (flexible numeric comparison)');
+        $this->assertResult(false, $c, ['x' => ['y' => 3, 'z' => 3]], 'Nested document does not match');
+
+        $c = new Matches(['x' => ['$$matchAsRoot' => ['y' => ['$$exists' => true]]]]);
+        $this->assertResult(true, $c, ['x' => ['y' => 2, 'z' => 3]], 'Nested document matches (special operators)');
+        $this->assertResult(false, $c, ['x' => ['z' => 3]], 'Nested document matches (special operators)');
+    }
+
     #[DataProvider('errorMessageProvider')]
     public function testErrorMessages($expectedMessageRegex, Matches $constraint, $actualValue): void
     {
@@ -302,6 +339,10 @@ public static function operatorErrorMessageProvider()
                 '$$sessionLsid requires string',
                 new Matches(['x' => ['$$sessionLsid' => 1]], new EntityMap()),
             ],
+            '$$matchAsDocument type' => [
+                '$$matchAsDocument requires a BSON document',
+                new Matches(['x' => ['$$matchAsDocument' => 'foo']]),
+            ],
         ];
     }
 
diff --git a/tests/UnifiedSpecTests/UnifiedSpecTest.php b/tests/UnifiedSpecTests/UnifiedSpecTest.php
index 9f47f745b..1c4df0478 100644
--- a/tests/UnifiedSpecTests/UnifiedSpecTest.php
+++ b/tests/UnifiedSpecTests/UnifiedSpecTest.php
@@ -43,6 +43,7 @@ class UnifiedSpecTest extends FunctionalTestCase
         'crud/replaceOne-sort' => 'Sort for replace operations is not supported (PHPLIB-1492)',
         'crud/updateOne-sort' => 'Sort for update operations is not supported (PHPLIB-1492)',
         'crud/bypassDocumentValidation' => 'bypassDocumentValidation is handled by libmongoc (PHPLIB-1576)',
+        'crud/distinct-hint' => 'Hint for distinct operations is not supported (PHPLIB-1582)',
     ];
 
     /** @var array<string, string> */
@@ -60,7 +61,7 @@ class UnifiedSpecTest extends FunctionalTestCase
         'valid-pass/expectedEventsForClient-eventType: eventType defaults to command if unset' => 'PHPC does not implement CMAP',
         // CSOT is not yet implemented (PHPC-1760)
         'valid-pass/collectionData-createOptions: collection is created with the correct options' => 'CSOT is not yet implemented (PHPC-1760)',
-        'valid-pass/matches-lte-operator: special lte matching operator' => 'CSOT is not yet implemented (PHPC-1760)',
+        'valid-pass/operator-lte: special lte matching operator' => 'CSOT is not yet implemented (PHPC-1760)',
         // libmongoc always adds readConcern to aggregate command
         'index-management/search index operations ignore read and write concern: listSearchIndexes ignores read and write concern' => 'libmongoc appends readConcern to aggregate command',
         // Uses an invalid object name
diff --git a/tests/UnifiedSpecTests/UnifiedTestRunner.php b/tests/UnifiedSpecTests/UnifiedTestRunner.php
index 93d3a3421..92dd0f61a 100644
--- a/tests/UnifiedSpecTests/UnifiedTestRunner.php
+++ b/tests/UnifiedSpecTests/UnifiedTestRunner.php
@@ -61,7 +61,7 @@ final class UnifiedTestRunner
      *   - 1.9: Only createEntities operation is implemented
      *   - 1.10: Not implemented
      *   - 1.11: Not implemented, but CMAP is not applicable
-     *   - 1.13: Not implemented
+     *   - 1.13: Only $$matchAsDocument and $$matchAsRoot is implemented
      *   - 1.14: Not implemented
      */
     public const MAX_SCHEMA_VERSION = '1.15';
diff --git a/tests/specifications b/tests/specifications
index b1b5a7f42..daf9e0744 160000
--- a/tests/specifications
+++ b/tests/specifications
@@ -1 +1 @@
-Subproject commit b1b5a7f4209ba4a0fd3dca31a7b34378ac5ce6c1
+Subproject commit daf9e0744692d1e48a8a2d90d585602ea965e520