diff --git a/vision_agent/utils/execute.py b/vision_agent/utils/execute.py
index 270cd0bb..8bed99fa 100644
--- a/vision_agent/utils/execute.py
+++ b/vision_agent/utils/execute.py
@@ -7,6 +7,7 @@
 import sys
 import traceback
 import warnings
+import json
 from enum import Enum
 from pathlib import Path
 from time import sleep
@@ -243,8 +244,8 @@ def __str__(self) -> str:
             f"----- stdout -----\n{stdout_str}\n----- stderr -----\n{stderr_str}"
         )
 
-    def to_json(self) -> str:
-        return str(self)
+    def to_json(self) -> bytes:
+        return {"stdout": self.stdout, "stderr": self.stderr}
 
 
 class Error(BaseModel):