diff --git a/engine/train.py b/engine/train.py
index 3a7dd2c..54fa203 100644
--- a/engine/train.py
+++ b/engine/train.py
@@ -457,6 +457,8 @@ def run_local(overrides: dict) -> dict:
             should_print = True
     if should_print:
         print(json.dumps(metrics, indent=2))
+        # sentinel line for machine-readable extraction; must stay on one line
+        print("PHANTOM_METRICS:" + json.dumps(metrics))
     return metrics