diff --git a/src/levanter/infra/tpus.py b/src/levanter/infra/tpus.py
index c47d79d46..c635cc88b 100644
--- a/src/levanter/infra/tpus.py
+++ b/src/levanter/infra/tpus.py
@@ -203,8 +203,14 @@ def add_ssh_key(ssh_key_filename):
     # have to make sure .ssh exists
     os.makedirs(os.path.expanduser("~/.ssh"), exist_ok=True)
     try:
-        key_hash = subprocess.check_output(["ssh-keygen", "-lf", ssh_key_filename]).decode("utf-8").split()[1]
-        existing_keys = subprocess.check_output(["ssh-add", "-l"]).decode("utf-8").split("\n")
+        key_hash = (
+            subprocess.check_output(["ssh-keygen", "-lf", ssh_key_filename], stderr=subprocess.STDOUT)
+            .decode("utf-8")
+            .split()[1]
+        )
+        existing_keys = (
+            subprocess.check_output(["ssh-add", "-l"], stderr=subprocess.STDOUT).decode("utf-8").split("\n")
+        )
         for key in existing_keys:
             if key_hash in key:
                 return