diff --git a/src/Plugins/Shard.php b/src/Plugins/Shard.php
index 814125f20..e9f1ece1d 100644
--- a/src/Plugins/Shard.php
+++ b/src/Plugins/Shard.php
@@ -187,15 +187,14 @@ private function handleUpdateShards(array $arguments): array
      */
     private function allTests(array $arguments): array
     {
-        $output = (new Process([
-            'php',
-            ...$this->removeParallelArguments($arguments),
-            '--list-tests',
-        ]))->setTimeout(120)->mustRun()->getOutput();
+        $command = $this->buildListTestsCommand(
+            $arguments,
+            TestSuite::getInstance()->testPath,
+        );
 
-        preg_match_all('/ - (?:P\\\\)?(Tests\\\\[^:]+)::/', $output, $matches);
+        $output = (new Process($command))->setTimeout(120)->mustRun()->getOutput();
 
-        return array_values(array_unique($matches[1]));
+        return $this->parseListTestsOutput($output);
     }
 
     /**
@@ -204,7 +203,36 @@ private function allTests(array $arguments): array
      */
     private function removeParallelArguments(array $arguments): array
     {
-        return array_filter($arguments, fn (string $argument): bool => ! in_array($argument, ['--parallel', '-p'], strict: true));
+        return array_values(array_filter(
+            $arguments,
+            fn (string $argument): bool => ! in_array($argument, ['--parallel', '-p'], strict: true)
+                && ! str_starts_with($argument, '--processes'),
+        ));
+    }
+
+    /**
+     * Builds the subprocess command used to enumerate tests via `--list-tests`.
+     *
+     * @param  list<string>  $arguments
+     * @return list<string>
+     */
+    private function buildListTestsCommand(array $arguments, string $testPath): array
+    {
+        $filtered = $this->removeParallelArguments($arguments);
+
+        return ['php', ...$filtered, '--test-directory='.$testPath, '--list-tests'];
+    }
+
+    /**
+     * Parses `--list-tests` output into a unique list of test class FQCNs.
+     *
+     * @return list<string>
+     */
+    private function parseListTestsOutput(string $output): array
+    {
+        preg_match_all('/ - (?:P\\\\)?([A-Za-z_]\w*(?:\\\\[A-Za-z_]\w*)*)::/', $output, $matches);
+
+        return array_values(array_unique($matches[1]));
     }
 
     /**
diff --git a/tests/.snapshots/success.txt b/tests/.snapshots/success.txt
index 58dbeddf4..177581058 100644
--- a/tests/.snapshots/success.txt
+++ b/tests/.snapshots/success.txt
@@ -1938,4 +1938,4 @@
   ✓ pass with dataset with ('my-datas-set-value')
   ✓ within describe → pass with dataset with ('my-datas-set-value')
 
-  Tests:    2 deprecated, 4 warnings, 5 incomplete, 2 notices, 40 todos, 35 skipped, 1329 passed (3010 assertions)
\ No newline at end of file
+  Tests:    2 deprecated, 4 warnings, 5 incomplete, 2 notices, 40 todos, 35 skipped, 1329 passed (3010 assertions)
diff --git a/tests/Unit/Plugins/Shard.php b/tests/Unit/Plugins/Shard.php
new file mode 100644
index 000000000..53766b5d6
--- /dev/null
+++ b/tests/Unit/Plugins/Shard.php
@@ -0,0 +1,144 @@
+<?php
+
+use Pest\Plugins\Shard;
+use Symfony\Component\Console\Output\NullOutput;
+
+$shard = new Shard(new NullOutput);
+$invoke = function (string $method, mixed ...$args) use ($shard): mixed {
+    $ref = new ReflectionMethod(Shard::class, $method);
+
+    return $ref->invoke($shard, ...$args);
+};
+
+it('parses Tests\\ namespaced classes from --list-tests output', function () use ($invoke) {
+    $output = <<<'OUT'
+ INFO  Available tests:
+
+ - P\Tests\Features\After::__pest_evaluable_it_runs
+ - P\Tests\Features\After::__pest_evaluable_it_runs_twice
+ - P\Tests\Unit\Foo::test_bar
+OUT;
+
+    expect($invoke('parseListTestsOutput', $output))->toBe([
+        'Tests\\Features\\After',
+        'Tests\\Unit\\Foo',
+    ]);
+});
+
+it('deduplicates repeated class names from multiple test methods', function () use ($invoke) {
+    $output = <<<'OUT'
+ - P\Tests\Same::method_a
+ - P\Tests\Same::method_b
+ - P\Tests\Same::method_c
+OUT;
+
+    expect($invoke('parseListTestsOutput', $output))->toBe(['Tests\\Same']);
+});
+
+it('returns an empty list for output with no matching lines', function () use ($invoke) {
+    expect($invoke('parseListTestsOutput', ''))->toBe([])
+        ->and($invoke('parseListTestsOutput', 'some random text'))->toBe([]);
+});
+
+it('parses non-Tests namespaced classes', function () use ($invoke) {
+    $output = <<<'OUT'
+ - P\Acme\Sharding\OneTest::test_foo
+ - P\Acme\Sharding\TwoTest::test_bar
+ - App\Suite\BazTest::test_qux
+OUT;
+
+    expect($invoke('parseListTestsOutput', $output))->toBe([
+        'Acme\\Sharding\\OneTest',
+        'Acme\\Sharding\\TwoTest',
+        'App\\Suite\\BazTest',
+    ]);
+});
+
+it('parses unnamespaced top-level classes', function () use ($invoke) {
+    $output = ' - P\FooTest::test_bar';
+
+    expect($invoke('parseListTestsOutput', $output))->toBe(['FooTest']);
+});
+
+it('strips the P\\ Pest prefix but keeps the rest of the FQCN', function () use ($invoke) {
+    $output = <<<'OUT'
+ - P\Acme\OneTest::a
+ - Acme\TwoTest::b
+OUT;
+
+    expect($invoke('parseListTestsOutput', $output))->toBe([
+        'Acme\\OneTest',
+        'Acme\\TwoTest',
+    ]);
+});
+
+it('ignores junk lines that lack the " - …::" framing', function () use ($invoke) {
+    $output = <<<'OUT'
+ INFO  Available tests:
+
+There were errors:
+garbage ::: not a test
+ - P\Acme\RealTest::method
+OUT;
+
+    expect($invoke('parseListTestsOutput', $output))->toBe(['Acme\\RealTest']);
+});
+
+it('builds the list-tests command with the forwarded --test-directory', function () use ($invoke) {
+    $command = $invoke('buildListTestsCommand', ['bin/pest', '--update-shards'], 'custom/suite');
+
+    expect($command)->toBe([
+        'php',
+        'bin/pest',
+        '--update-shards',
+        '--test-directory=custom/suite',
+        '--list-tests',
+    ]);
+});
+
+it('strips --parallel and -p when building the list-tests command', function () use ($invoke) {
+    $command = $invoke('buildListTestsCommand',
+        ['bin/pest', '--parallel', '--update-shards', '-p'],
+        'tests',
+    );
+
+    expect($command)->toBe([
+        'php',
+        'bin/pest',
+        '--update-shards',
+        '--test-directory=tests',
+        '--list-tests',
+    ]);
+});
+
+it('forwards --test-directory even when input arguments include one', function () use ($invoke) {
+    $command = $invoke('buildListTestsCommand', ['bin/pest'], 'suites');
+
+    expect($command)->toContain('--test-directory=suites');
+});
+
+it('strips --processes=N when building the list-tests command', function () use ($invoke) {
+    $command = $invoke('buildListTestsCommand',
+        ['bin/pest', '--parallel', '--processes=4', '--update-shards'],
+        'tests',
+    );
+
+    expect($command)->toBe([
+        'php',
+        'bin/pest',
+        '--update-shards',
+        '--test-directory=tests',
+        '--list-tests',
+    ]);
+});
+
+it('strips --processes N (space-separated) when building the list-tests command', function () use ($invoke) {
+    $command = $invoke('buildListTestsCommand',
+        ['bin/pest', '--parallel', '--processes', '4', '--update-shards'],
+        'tests',
+    );
+
+    expect($command)->not->toContain('--processes')
+        ->and($command)->toContain('--update-shards')
+        ->and($command)->toContain('--test-directory=tests');
+});