diff --git a/agents-api.php b/agents-api.php
index 95be7e1..aebec6f 100644
--- a/agents-api.php
+++ b/agents-api.php
@@ -79,7 +79,8 @@
 	};
 
 	$agents_api_symbol_files = array_merge(
-		glob( __DIR__ . '/src/*/{class,interface}-*.php', GLOB_BRACE ) ?: array(),
+		glob( __DIR__ . '/src/*/class-*.php' ) ?: array(),
+		glob( __DIR__ . '/src/*/interface-*.php' ) ?: array(),
 		array( __DIR__ . '/src/Channels/register-default-agents-chat-handler.php' )
 	);
 	foreach ( $agents_api_symbol_files as $agents_api_symbol_file ) {
diff --git a/tests/bootstrap-version-skew-smoke.php b/tests/bootstrap-version-skew-smoke.php
index 37a2607..1cad6de 100644
--- a/tests/bootstrap-version-skew-smoke.php
+++ b/tests/bootstrap-version-skew-smoke.php
@@ -32,6 +32,11 @@ function agents_api_copy_directory( string $source, string $destination ): void
 
 agents_api_copy_directory( $root . '/src', $old_copy . '/src' );
 $old_bootstrap = (string) file_get_contents( $root . '/agents-api.php' );
+if ( str_contains( $old_bootstrap, 'GLOB_BRACE' ) ) {
+	fwrite( STDERR, "FAIL: bootstrap discovery depends on the optional GLOB_BRACE flag.\n" );
+	exit( 1 );
+}
+
 $old_bootstrap = str_replace(
 	"require_once AGENTS_API_PATH . 'src/Channels/class-wp-agent-channel.php';\n",
 	'',
@@ -59,4 +64,4 @@ function agents_api_copy_directory( string $source, string $destination ): void
 	exit( 1 );
 }
 
-echo "PASS: newer copy tops up missing classes without repeating hooks.\n";
+echo "PASS: portable discovery tops up missing classes without repeating hooks.\n";