diff --git a/src/Plugins/Tia/Fingerprint.php b/src/Plugins/Tia/Fingerprint.php
index 0f4823a23..c3db69c19 100644
--- a/src/Plugins/Tia/Fingerprint.php
+++ b/src/Plugins/Tia/Fingerprint.php
@@ -5,7 +5,8 @@
 namespace Pest\Plugins\Tia;
 
 use Pest\Plugins\Tia\Contracts\Lockfile;
-use Symfony\Component\Finder\Finder;
+use Symfony\Component\Process\Exception\ExceptionInterface as ProcessException;
+use Symfony\Component\Process\Process;
 
 /**
  * @internal
@@ -273,6 +274,9 @@ private static function trackedHash(string $projectRoot, string $relativePath):
      * Gitignored lockfiles (e.g. `package-lock.json` excluded from the repo)
      * regenerate per-machine with OS-specific optional deps, which would
      * otherwise force a fingerprint mismatch on every fetched baseline.
+     *
+     * Git itself answers the ignore question so that linked worktrees, whose
+     * `.git` is a pointer file, resolve against the right repository.
      */
     private static function isTrackedByGit(string $projectRoot, string $relativePath): bool
     {
@@ -292,13 +296,18 @@ private static function isTrackedByGit(string $projectRoot, string $relativePath
             return $cache[$key] = true;
         }
 
-        $finder = (new Finder)
-            ->in($projectRoot)
-            ->depth('== 0')
-            ->name($relativePath)
-            ->ignoreVCSIgnored(true);
+        $process = new Process(['git', 'check-ignore', '-q', '--', $relativePath], $projectRoot);
+        $process->setTimeout(5.0);
+
+        try {
+            $process->run();
+        } catch (ProcessException) {
+            return $cache[$key] = true;
+        }
 
-        return $cache[$key] = $finder->hasResults();
+        // 0: ignored. 1: not ignored. Anything else: git unavailable or not
+        // a repository, in which case the file is kept like the no-git path.
+        return $cache[$key] = $process->getExitCode() !== 0;
     }
 
     private static function contentHashOrNull(string $path): ?string
diff --git a/tests/Unit/Plugins/Tia/Fingerprint.php b/tests/Unit/Plugins/Tia/Fingerprint.php
new file mode 100644
index 000000000..734d7c44b
--- /dev/null
+++ b/tests/Unit/Plugins/Tia/Fingerprint.php
@@ -0,0 +1,109 @@
+<?php
+
+declare(strict_types=1);
+
+use Pest\Plugins\Tia\Fingerprint;
+use Symfony\Component\Process\Process;
+
+function fingerprintGit(string $cwd, string ...$args): void
+{
+    $process = new Process(['git', ...$args], $cwd);
+    $process->setTimeout(10.0);
+    $process->mustRun();
+}
+
+function fingerprintRepository(): string
+{
+    $root = sys_get_temp_dir().DIRECTORY_SEPARATOR.'pest_fingerprint_'.uniqid();
+    mkdir($root, 0777, true);
+
+    fingerprintGit($root, 'init', '-q');
+    fingerprintGit($root, 'config', 'user.email', 'pest@example.com');
+    fingerprintGit($root, 'config', 'user.name', 'Pest');
+
+    return $root;
+}
+
+function fingerprintRemoveDirectory(string $path): void
+{
+    if (! is_dir($path)) {
+        return;
+    }
+
+    $iterator = new RecursiveIteratorIterator(
+        new RecursiveDirectoryIterator($path, FilesystemIterator::SKIP_DOTS),
+        RecursiveIteratorIterator::CHILD_FIRST,
+    );
+
+    foreach ($iterator as $file) {
+        @chmod($file->getPathname(), 0777);
+        $file->isDir() ? @rmdir($file->getPathname()) : @unlink($file->getPathname());
+    }
+
+    @rmdir($path);
+}
+
+describe('compute()', function (): void {
+    it('fingerprints tracked structural files in a regular clone', function (): void {
+        $clone = fingerprintRepository();
+
+        try {
+            file_put_contents($clone.'/composer.lock', '{"packages": []}');
+            file_put_contents($clone.'/phpunit.xml', '<phpunit/>');
+            fingerprintGit($clone, 'add', '-A');
+            fingerprintGit($clone, 'commit', '-q', '-m', 'init');
+
+            $fingerprint = Fingerprint::compute($clone);
+
+            expect($fingerprint['structural']['composer_lock'])->not->toBeNull()
+                ->and($fingerprint['structural']['phpunit_xml'])->not->toBeNull();
+        } finally {
+            fingerprintRemoveDirectory($clone);
+        }
+    });
+
+    it('fingerprints tracked structural files inside a linked git worktree', function (): void {
+        $clone = fingerprintRepository();
+
+        try {
+            file_put_contents($clone.'/composer.lock', '{"packages": []}');
+            file_put_contents($clone.'/phpunit.xml', '<phpunit/>');
+            file_put_contents($clone.'/.gitignore', ".worktrees/\n");
+            fingerprintGit($clone, 'add', '-A');
+            fingerprintGit($clone, 'commit', '-q', '-m', 'init');
+            fingerprintGit($clone, 'worktree', 'add', '-q', '.worktrees/feature');
+
+            $worktree = $clone.'/.worktrees/feature';
+
+            $cloneFingerprint = Fingerprint::compute($clone);
+            $worktreeFingerprint = Fingerprint::compute($worktree);
+
+            expect($worktreeFingerprint['structural']['composer_lock'])->not->toBeNull()
+                ->and($worktreeFingerprint['structural']['phpunit_xml'])->not->toBeNull()
+                ->and($worktreeFingerprint['structural']['composer_lock'])->toBe($cloneFingerprint['structural']['composer_lock'])
+                ->and($worktreeFingerprint['structural']['phpunit_xml'])->toBe($cloneFingerprint['structural']['phpunit_xml']);
+        } finally {
+            fingerprintRemoveDirectory($clone);
+        }
+    });
+
+    it('excludes gitignored untracked files from the fingerprint', function (): void {
+        $clone = fingerprintRepository();
+
+        try {
+            file_put_contents($clone.'/composer.lock', '{"packages": []}');
+            file_put_contents($clone.'/.gitignore', "phpunit.xml\n");
+            fingerprintGit($clone, 'add', '-A');
+            fingerprintGit($clone, 'commit', '-q', '-m', 'init');
+
+            file_put_contents($clone.'/phpunit.xml', '<phpunit/>');
+
+            $fingerprint = Fingerprint::compute($clone);
+
+            expect($fingerprint['structural']['phpunit_xml'])->toBeNull()
+                ->and($fingerprint['structural']['composer_lock'])->not->toBeNull();
+        } finally {
+            fingerprintRemoveDirectory($clone);
+        }
+    });
+});