diff --git a/.gitattributes b/.gitattributes
new file mode 100644
index 0000000..eabea0d
--- /dev/null
+++ b/.gitattributes
@@ -0,0 +1,15 @@
+# Pollora harness (QA-06): development files stay out of the archive Composer downloads
+/.claude export-ignore
+/.gitattributes export-ignore
+/.github export-ignore
+/.gitignore export-ignore
+/.harness.json export-ignore
+/AGENTS.md export-ignore
+/api-surface.json export-ignore
+/composer-dependency-analyser.php export-ignore
+/phpstan.neon export-ignore
+/phpunit.xml.dist export-ignore
+/pint.json export-ignore
+/rector.php export-ignore
+/renovate.json export-ignore
+/tests export-ignore
diff --git a/.github/workflows/harness.yml b/.github/workflows/harness.yml
index ad6e301..0164122 100644
--- a/.github/workflows/harness.yml
+++ b/.github/workflows/harness.yml
@@ -14,6 +14,6 @@ permissions: {}
 
 jobs:
   harness:
-    uses: Pollora/harness/.github/workflows/php-package.yml@v0.1.8
+    uses: Pollora/harness/.github/workflows/php-package.yml@v0.1.15
     permissions:
       contents: read
diff --git a/composer.json b/composer.json
index 5472a49..dae5a35 100644
--- a/composer.json
+++ b/composer.json
@@ -31,7 +31,7 @@
         "pestphp/pest": "^3.8",
         "php-stubs/wordpress-stubs": "^7.1",
         "phpstan/phpstan": "^2.1",
-        "pollora/harness": "^0.1.8",
+        "pollora/harness": "^0.1.15",
         "szepeviktor/phpstan-wordpress": "^2.0"
     },
     "autoload": {
diff --git a/src/Collectors/WpHooksCollector.php b/src/Collectors/WpHooksCollector.php
index 5312896..6acac83 100644
--- a/src/Collectors/WpHooksCollector.php
+++ b/src/Collectors/WpHooksCollector.php
@@ -130,7 +130,7 @@ private static function describeClosure(\Closure $closure): string
         // A file included from a method (a mu-plugin WordPress loads from
         // Pollora's Bootstrap) gives its closures that class's scope: name
         // the class only when the closure is written in it
-        $scope = $scopeClass !== null && $scopeClass->getFileName() === $reflection->getFileName() ? $scopeClass->getName() : null;
+        $scope = $scopeClass instanceof \ReflectionClass && $scopeClass->getFileName() === $reflection->getFileName() ? $scopeClass->getName() : null;
 
         if (! str_contains($reflection->getName(), '{closure')) {
             return $scope !== null ? "{$scope}::{$reflection->getName()}" : $reflection->getName();