diff --git a/overrides/TextUI/TestSuiteFilterProcessor.php b/overrides/TextUI/TestSuiteFilterProcessor.php
index 64440ce2..536ab208 100644
--- a/overrides/TextUI/TestSuiteFilterProcessor.php
+++ b/overrides/TextUI/TestSuiteFilterProcessor.php
@@ -83,7 +83,7 @@ final readonly class TestSuiteFilterProcessor
         }
 
         if (Only::isEnabled()) {
-            $factory->addIncludeGroupFilter(['__pest_only']);
+            $factory->addIncludeGroupFilter([Only::group()]);
         } elseif ($configuration->hasGroups()) {
             $factory->addIncludeGroupFilter(
                 $configuration->groups(),
diff --git a/src/Functions.php b/src/Functions.php
index 77a078d7..401e1e3e 100644
--- a/src/Functions.php
+++ b/src/Functions.php
@@ -7,6 +7,7 @@ use Pest\Configuration;
 use Pest\Exceptions\AfterAllWithinDescribe;
 use Pest\Exceptions\BeforeAllWithinDescribe;
 use Pest\Expectation;
+use Pest\Mutate\Contracts\MutationTestRunner;
 use Pest\PendingCalls\AfterEachCall;
 use Pest\PendingCalls\BeforeEachCall;
 use Pest\PendingCalls\DescribeCall;
@@ -14,6 +15,7 @@ use Pest\PendingCalls\TestCall;
 use Pest\PendingCalls\UsesCall;
 use Pest\Repositories\DatasetsRepository;
 use Pest\Support\Backtrace;
+use Pest\Support\Container;
 use Pest\Support\DatasetInfo;
 use Pest\Support\HigherOrderTapProxy;
 use Pest\TestSuite;
@@ -222,7 +224,15 @@ if (! function_exists('covers')) {
     {
         $filename = Backtrace::file();
 
-        (new BeforeEachCall(TestSuite::getInstance(), $filename))
-            ->covers(...$classesOrFunctions);
+        $beforeEachCall = (new BeforeEachCall(TestSuite::getInstance(), $filename));
+
+        $beforeEachCall->covers(...$classesOrFunctions);
+
+        /** @var MutationTestRunner $runner */
+        $runner = Container::getInstance()->get(MutationTestRunner::class);
+
+        if ($runner->isEnabled()) {
+            $beforeEachCall->only('__pest_mutate_only');
+        }
     }
 }
diff --git a/src/PendingCalls/TestCall.php b/src/PendingCalls/TestCall.php
index a9befed1..6e461dc2 100644
--- a/src/PendingCalls/TestCall.php
+++ b/src/PendingCalls/TestCall.php
@@ -225,7 +225,7 @@ final class TestCall
      */
     public function only(): self
     {
-        Only::enable($this);
+        Only::enable($this, ...func_get_args()); // @phpstan-ignore-line
 
         return $this;
     }
@@ -523,7 +523,8 @@ final class TestCall
         $classesOrFunctions = array_reduce($classesOrFunctions, fn ($carry, $item): array => is_array($item) ? array_merge($carry, $item) : array_merge($carry, [$item]), []); // @pest-ignore-type
 
         foreach ($classesOrFunctions as $classOrFunction) {
-            $isClass = class_exists($classOrFunction) || trait_exists($classOrFunction) || interface_exists($classOrFunction) || enum_exists($classOrFunction);
+            $isClass = class_exists($classOrFunction) || interface_exists($classOrFunction) || enum_exists($classOrFunction);
+            $isTrait = trait_exists($classOrFunction);
             $isFunction = function_exists($classOrFunction);
 
             if (! $isClass && ! $isFunction) {
@@ -532,6 +533,8 @@ final class TestCall
 
             if ($isClass) {
                 $this->coversClass($classOrFunction);
+            } elseif ($isTrait) {
+                $this->coversTrait($classOrFunction);
             } else {
                 $this->coversFunction($classOrFunction);
             }
@@ -559,6 +562,25 @@ final class TestCall
         return $this;
     }
 
+    /**
+     * Sets the covered classes.
+     */
+    public function coversTrait(string ...$traits): self
+    {
+        foreach ($traits as $trait) {
+            $this->testCaseFactoryAttributes[] = new Attribute(
+                \PHPUnit\Framework\Attributes\CoversTrait::class,
+                [$trait],
+            );
+        }
+
+        /** @var Configuration $configuration */
+        $configuration = Container::getInstance()->get(ConfigurationRepository::class)->globalConfiguration('default'); // @phpstan-ignore-line
+        $configuration->class(...$traits); // @phpstan-ignore-line
+
+        return $this;
+    }
+
     /**
      * Sets the covered functions.
      */
diff --git a/src/Plugins/Only.php b/src/Plugins/Only.php
index 5ffce81e..977723cc 100644
--- a/src/Plugins/Only.php
+++ b/src/Plugins/Only.php
@@ -38,18 +38,26 @@ final class Only implements Terminable
     /**
      * Creates the lock file.
      */
-    public static function enable(TestCall $testCall): void
+    public static function enable(TestCall $testCall, string $group = '__pest_only'): void
     {
         if (Environment::name() === Environment::CI) {
             return;
         }
 
-        $testCall->group('__pest_only');
+        $testCall->group($group);
 
         $lockFile = self::TEMPORARY_FOLDER.DIRECTORY_SEPARATOR.'only.lock';
 
+        if (file_exists($lockFile) && $group === '__pest_only') {
+            file_put_contents($lockFile, $group);
+
+            return;
+        }
+
         if (! file_exists($lockFile)) {
             touch($lockFile);
+
+            file_put_contents($lockFile, $group);
         }
     }
 
@@ -62,4 +70,18 @@ final class Only implements Terminable
 
         return file_exists($lockFile);
     }
+
+    /**
+     * Returns the group name.
+     */
+    public static function group(): string
+    {
+        $lockFile = self::TEMPORARY_FOLDER.DIRECTORY_SEPARATOR.'only.lock';
+
+        if (! file_exists($lockFile)) {
+            return '__pest_only';
+        }
+
+        return file_get_contents($lockFile) ?: '__pest_only'; // @phpstan-ignore-line
+    }
 }
diff --git a/tests/Features/Covers.php b/tests/Features/Covers.php
index 719329a4..c7721aa8 100644
--- a/tests/Features/Covers.php
+++ b/tests/Features/Covers.php
@@ -41,9 +41,9 @@ it('guesses if the given argument is a class or function', function () {
 it('uses the correct PHPUnit attribute for trait', function () {
     $attributes = (new ReflectionClass($this))->getAttributes();
 
-    expect($attributes[8]->getName())->toBe('PHPUnit\Framework\Attributes\CoversClass');
+    expect($attributes[8]->getName())->toBe('PHPUnit\Framework\Attributes\CoversTrait');
     expect($attributes[8]->getArguments()[0])->toBe('Tests\Fixtures\Covers\CoversTrait');
-})->coversClass(CoversTrait::class);
+})->coversTrait(CoversTrait::class);
 
 it('uses the correct PHPUnit attribute for covers nothing', function () {
     $attributes = (new ReflectionMethod($this, $this->name()))->getAttributes();
diff --git a/tests/Visual/Parallel.php b/tests/Visual/Parallel.php
index 3ca89d4e..6d1fc4c5 100644
--- a/tests/Visual/Parallel.php
+++ b/tests/Visual/Parallel.php
@@ -16,7 +16,7 @@ $run = function () {
 
 test('parallel', function () use ($run) {
     expect($run('--exclude-group=integration'))
-        ->toContain('Tests:    2 deprecated, 4 warnings, 5 incomplete, 2 notices, 17 todos, 19 skipped, 1081 passed (2600 assertions)')
+        ->toContain('Tests:    2 deprecated, 4 warnings, 5 incomplete, 2 notices, 17 todos, 28 skipped, 1091 passed (2624 assertions)')
         ->toContain('Parallel: 3 processes');
 })->skipOnWindows();