diff --git a/loopx/cli_commands/refresh_settlement.py b/loopx/cli_commands/refresh_settlement.py
index 6a8fb21873..522d4dbf2a 100644
--- a/loopx/cli_commands/refresh_settlement.py
+++ b/loopx/cli_commands/refresh_settlement.py
@@ -65,7 +65,7 @@ def settle_refreshed_turn(
         # call the lower-level debit without its receipt-producing adapter.
         result = subprocess.run(
             [sys.executable, "-m", "loopx.cli", "--format", "json", *command[1:]],
-            capture_output=True, text=True, timeout=60, check=False,
+            capture_output=True, text=True, encoding="utf-8", timeout=60, check=False,
         )
         value = json.loads(result.stdout)
         if not isinstance(value, dict):
diff --git a/loopx/control_plane/turn_driver/codex_context.py b/loopx/control_plane/turn_driver/codex_context.py
index b7d7879f1f..8b1b8f4fbb 100644
--- a/loopx/control_plane/turn_driver/codex_context.py
+++ b/loopx/control_plane/turn_driver/codex_context.py
@@ -163,7 +163,7 @@ def _locked(directory: str) -> Iterator[Path]:
 
     root = _private_root(directory)
     fd = os.open(root / "lock", os.O_CREAT | os.O_RDWR | os.O_NOFOLLOW | os.O_NONBLOCK, 0o600)
-    with os.fdopen(fd, "r+") as lock:
+    with os.fdopen(fd, "r+", encoding="utf-8") as lock:
         if not stat.S_ISREG(os.fstat(lock.fileno()).st_mode):
             raise ValueError("context lock is not a regular file")
         fcntl.flock(lock, fcntl.LOCK_EX)