diff --git a/litellm/llms/xai/oauth.py b/litellm/llms/xai/oauth.py
index a773e78c35a..55d90a78858 100644
--- a/litellm/llms/xai/oauth.py
+++ b/litellm/llms/xai/oauth.py
@@ -194,7 +194,11 @@ class XAIOAuthAuthenticator:
         return self.http_client or _get_httpx_client()
 
     def _ensure_token_dir(self) -> None:
-        os.makedirs(self.token_dir, exist_ok=True)
+        os.makedirs(self.token_dir, mode=0o700, exist_ok=True)
+        try:
+            os.chmod(self.token_dir, 0o700)
+        except OSError:
+            verbose_logger.debug("Could not chmod xAI OAuth token directory")
 
     def _read_auth_file(self) -> Optional[Dict[str, Any]]:
         try:
@@ -206,12 +210,34 @@ class XAIOAuthAuthenticator:
 
     def _write_auth_file(self, data: Dict[str, Any]) -> None:
         self._ensure_token_dir()
-        with open(self.auth_file, "w") as f:
-            json.dump(data, f)
+        tmp_file = os.path.join(
+            self.token_dir,
+            f".{os.path.basename(self.auth_file)}.{uuid.uuid4().hex}.tmp",
+        )
+        flags = os.O_WRONLY | os.O_CREAT | os.O_EXCL
+        if hasattr(os, "O_NOFOLLOW"):
+            flags |= os.O_NOFOLLOW
+        fd = os.open(tmp_file, flags, 0o600)
         try:
-            os.chmod(self.auth_file, 0o600)
-        except OSError:
-            verbose_logger.debug("Could not chmod xAI OAuth auth file")
+            with os.fdopen(fd, "w") as f:
+                json.dump(data, f)
+                f.flush()
+                os.fsync(f.fileno())
+            os.replace(tmp_file, self.auth_file)
+            try:
+                os.chmod(self.auth_file, 0o600)
+            except OSError:
+                verbose_logger.debug("Could not chmod xAI OAuth auth file")
+        except Exception:
+            try:
+                os.close(fd)
+            except OSError:
+                pass
+            try:
+                os.unlink(tmp_file)
+            except OSError:
+                pass
+            raise
 
     def _is_expired(self, auth_data: Dict[str, Any]) -> bool:
         expires_at = auth_data.get("expires_at")
@@ -223,10 +249,15 @@ class XAIOAuthAuthenticator:
             return True
 
     def _discover(self) -> Dict[str, str]:
-        response = self._client().get(
-            XAI_OAUTH_DISCOVERY_URL, headers={"Accept": "application/json"}
-        )
-        response.raise_for_status()
+        try:
+            response = self._client().get(
+                XAI_OAUTH_DISCOVERY_URL, headers={"Accept": "application/json"}
+            )
+            response.raise_for_status()
+        except httpx.HTTPStatusError as exc:
+            raise XAIOAuthError(
+                f"xAI OAuth discovery request failed: {exc.response.status_code} {exc.response.text}"
+            ) from exc
         data = response.json()
         authorization_endpoint = data.get("authorization_endpoint")
         token_endpoint = data.get("token_endpoint")
diff --git a/tests/test_litellm/llms/xai/test_xai_oauth.py b/tests/test_litellm/llms/xai/test_xai_oauth.py
index 3f394244e5d..ea137067886 100644
--- a/tests/test_litellm/llms/xai/test_xai_oauth.py
+++ b/tests/test_litellm/llms/xai/test_xai_oauth.py
@@ -195,17 +195,34 @@ def test_write_auth_file_creates_private_file(tmp_path, monkeypatch):
     token_dir = tmp_path / "xai_oauth"
     monkeypatch.setenv("XAI_OAUTH_TOKEN_DIR", str(token_dir))
     authenticator = XAIOAuthAuthenticator()
+    old_umask = os.umask(0o022)
+    replace_calls = []
+    real_replace = os.replace
 
-    authenticator._write_auth_file(
-        {
-            "access_token": "access-token",
-            "refresh_token": "refresh-token",
-            "expires_at": time.time() + 3600,
-        }
-    )
+    def assert_private_temp_file(src, dst):
+        replace_calls.append((src, dst))
+        assert oct(os.stat(src).st_mode & 0o777) == "0o600"
+        with open(src) as f:
+            assert json.load(f)["refresh_token"] == "refresh-token"
+        real_replace(src, dst)
+
+    monkeypatch.setattr(os, "replace", assert_private_temp_file)
+
+    try:
+        authenticator._write_auth_file(
+            {
+                "access_token": "access-token",
+                "refresh_token": "refresh-token",
+                "expires_at": time.time() + 3600,
+            }
+        )
+    finally:
+        os.umask(old_umask)
 
     stored = json.loads((token_dir / "auth.json").read_text())
     assert stored["access_token"] == "access-token"
+    assert replace_calls
+    assert oct(os.stat(token_dir).st_mode & 0o777) == "0o700"
     assert oct(os.stat(token_dir / "auth.json").st_mode & 0o777) == "0o600"
 
 
@@ -251,6 +268,25 @@ def test_discover_requires_authorization_and_token_endpoints():
         authenticator._discover()
 
 
+def test_discover_wraps_http_errors():
+    authenticator = XAIOAuthAuthenticator(
+        http_client=httpx.Client(
+            transport=httpx.MockTransport(
+                lambda request: httpx.Response(
+                    500, text="discovery failed", request=request
+                )
+            )
+        )
+    )
+
+    with pytest.raises(XAIOAuthError) as exc_info:
+        authenticator._discover()
+
+    assert "xAI OAuth discovery request failed: 500 discovery failed" in str(
+        exc_info.value
+    )
+
+
 def test_refresh_discovers_token_endpoint_when_auth_file_is_legacy(
     tmp_path, monkeypatch
 ):