diff --git a/singer_sdk/authenticators.py b/singer_sdk/authenticators.py
index 21ef1ba22..c6478cb92 100644
--- a/singer_sdk/authenticators.py
+++ b/singer_sdk/authenticators.py
@@ -79,7 +79,12 @@ def __call__(cls, *args: t.Any, **kwargs: t.Any) -> t.Any:  # noqa: ANN401
 
 
 class APIAuthenticatorBase:
-    """Base class for offloading API auth."""
+    """Base class for offloading API auth.
+
+    Attributes:
+        auth_headers: HTTP headers for authentication.
+        auth_params: URL query parameters for authentication.
+    """
 
     def __init__(self, stream: RESTStream) -> None:
         """Init authenticator.
@@ -89,8 +94,8 @@ def __init__(self, stream: RESTStream) -> None:
         """
         self.tap_name: str = stream.tap_name
         self._config: dict[str, t.Any] = dict(stream.config)
-        self._auth_headers: dict[str, t.Any] = {}
-        self._auth_params: dict[str, t.Any] = {}
+        self.auth_headers: dict[str, t.Any] = {}
+        self.auth_params: dict[str, t.Any] = {}
         self.logger: logging.Logger = stream.logger
 
     @property
@@ -102,24 +107,6 @@ def config(self) -> t.Mapping[str, t.Any]:
         """
         return MappingProxyType(self._config)
 
-    @property
-    def auth_headers(self) -> dict:
-        """Get headers.
-
-        Returns:
-            HTTP headers for authentication.
-        """
-        return self._auth_headers or {}
-
-    @property
-    def auth_params(self) -> dict:
-        """Get query parameters.
-
-        Returns:
-            URL query parameters for authentication.
-        """
-        return self._auth_params or {}
-
     def authenticate_request(
         self,
         request: requests.PreparedRequest,
@@ -177,10 +164,10 @@ def __init__(
             auth_headers: Authentication headers.
         """
         super().__init__(stream=stream)
-        if self._auth_headers is None:
-            self._auth_headers = {}
+        if self.auth_headers is None:
+            self.auth_headers = {}
         if auth_headers:
-            self._auth_headers.update(auth_headers)
+            self.auth_headers.update(auth_headers)
 
 
 class APIKeyAuthenticator(APIAuthenticatorBase):
@@ -218,13 +205,13 @@ def __init__(
             raise ValueError(msg)
 
         if location == "header":
-            if self._auth_headers is None:
-                self._auth_headers = {}
-            self._auth_headers.update(auth_credentials)
+            if self.auth_headers is None:
+                self.auth_headers = {}
+            self.auth_headers.update(auth_credentials)
         elif location == "params":
-            if self._auth_params is None:
-                self._auth_params = {}
-            self._auth_params.update(auth_credentials)
+            if self.auth_params is None:
+                self.auth_params = {}
+            self.auth_params.update(auth_credentials)
 
     @classmethod
     def create_for_stream(
@@ -267,9 +254,9 @@ def __init__(self, stream: RESTStream, token: str) -> None:
         super().__init__(stream=stream)
         auth_credentials = {"Authorization": f"Bearer {token}"}
 
-        if self._auth_headers is None:
-            self._auth_headers = {}
-        self._auth_headers.update(auth_credentials)
+        if self.auth_headers is None:
+            self.auth_headers = {}
+        self.auth_headers.update(auth_credentials)
 
     @classmethod
     def create_for_stream(
@@ -326,9 +313,9 @@ def __init__(
         auth_token = base64.b64encode(credentials).decode("ascii")
         auth_credentials = {"Authorization": f"Basic {auth_token}"}
 
-        if self._auth_headers is None:
-            self._auth_headers = {}
-        self._auth_headers.update(auth_credentials)
+        if self.auth_headers is None:
+            self.auth_headers = {}
+        self.auth_headers.update(auth_credentials)
 
     @classmethod
     def create_for_stream(
@@ -383,20 +370,23 @@ def __init__(
         self.last_refreshed: datetime.datetime | None = None
         self.expires_in: int | None = None
 
-    @property
-    def auth_headers(self) -> dict:
-        """Return a dictionary of auth headers to be applied.
+    def authenticate_request(
+        self,
+        request: requests.PreparedRequest,
+    ) -> requests.PreparedRequest:
+        """Authenticate an OAuth request.
 
-        These will be merged with any `http_headers` specified in the stream.
+        Args:
+            request: A :class:`requests.PreparedRequest` object.
 
         Returns:
-            HTTP headers for authentication.
+            The authenticated request object.
         """
         if not self.is_token_valid():
             self.update_access_token()
-        result = super().auth_headers
-        result["Authorization"] = f"Bearer {self.access_token}"
-        return result
+
+        self.auth_headers["Authorization"] = f"Bearer {self.access_token}"
+        return super().authenticate_request(request)
 
     @property
     def auth_endpoint(self) -> str: