diff --git a/sdks/python/pmxt/ws_client.py b/sdks/python/pmxt/ws_client.py
index bc93c362..2cf0a9bb 100644
--- a/sdks/python/pmxt/ws_client.py
+++ b/sdks/python/pmxt/ws_client.py
@@ -140,7 +140,9 @@ def _ensure_connected(self) -> None:
 
         # Connection attempts default to CONNECT_ATTEMPTS; callers may override
         # via the "maxReconnectAttempts" config key.
-        max_attempts = self._config.get("maxReconnectAttempts") or CONNECT_ATTEMPTS
+        max_attempts = self._config.get("maxReconnectAttempts")
+        if max_attempts is None:
+            max_attempts = CONNECT_ATTEMPTS
         # When "reconnectInterval" (ms) is not configured, preserve the fast
         # default backoff (0.25s, 0.5s, ...). Only a longer, explicitly
         # configured interval overrides it.
diff --git a/sdks/python/tests/test_ws_client.py b/sdks/python/tests/test_ws_client.py
index 13c9771c..3880577a 100644
--- a/sdks/python/tests/test_ws_client.py
+++ b/sdks/python/tests/test_ws_client.py
@@ -4,7 +4,10 @@
 import sys
 import types
 
+import pytest
+
 import pmxt.ws_client as ws_client
+from pmxt.errors import PmxtError
 from pmxt.ws_client import SidecarWsClient, _WsSubscription, _connect_websocket
 
 
@@ -147,6 +150,34 @@ def test_ws_config_custom_url_and_reconnect_interval(monkeypatch):
     assert sleeps == [2.0]
 
 
+def test_ws_none_reconnect_attempts_uses_default(monkeypatch):
+    urls = []
+    _install_failing_websocket(monkeypatch, urls)
+
+    client = SidecarWsClient(
+        "http://localhost:3847", config={"maxReconnectAttempts": None}
+    )
+    with pytest.raises(OSError, match="handshake failure"):
+        with client._lock:
+            client._ensure_connected()
+
+    assert len(urls) == 3
+
+
+def test_ws_zero_reconnect_attempts_is_honored(monkeypatch):
+    urls = []
+    _install_failing_websocket(monkeypatch, urls)
+
+    client = SidecarWsClient(
+        "http://localhost:3847", config={"maxReconnectAttempts": 0}
+    )
+    with pytest.raises(PmxtError, match="WebSocket connection failed"):
+        with client._lock:
+            client._ensure_connected()
+
+    assert urls == []
+
+
 def test_ws_default_backoff_is_fast(monkeypatch):
     """Regression: the default reconnect backoff must stay 0.25s/0.5s, not a
     flat multi-second sleep, unless an interval is explicitly configured."""