diff --git a/src/ValueObjects/ToolCall.php b/src/ValueObjects/ToolCall.php
index 7329979ed..7e7ed1385 100644
--- a/src/ValueObjects/ToolCall.php
+++ b/src/ValueObjects/ToolCall.php
@@ -36,11 +36,13 @@ public function arguments(): array
 
             $arguments = $this->arguments;
 
-            return json_decode(
+            $decoded = json_decode(
                 $arguments,
                 true,
                 flags: JSON_THROW_ON_ERROR
             );
+
+            return is_array($decoded) ? $decoded : [];
         }
 
         /** @var array<string, mixed> $arguments */