1 files changed, 3 insertions, 1 deletions
diff --git a/synapse/api/errors.py b/synapse/api/errors.py
index fcfdf8bd2b..a3b0c0a3e4 100644
--- a/synapse/api/errors.py
+++ b/synapse/api/errors.py
@@ -239,14 +239,16 @@ class InteractiveAuthIncompleteError(Exception):
     (This indicates we should return a 401 with 'result' as the body)
 
     Attributes:
+        session_id: The ID of the ongoing interactive auth session.
         result: the server response to the request, which should be
             passed back to the client
     """
 
-    def __init__(self, result: "JsonDict"):
+    def __init__(self, session_id: str, result: "JsonDict"):
         super(InteractiveAuthIncompleteError, self).__init__(
             "Interactive auth not yet complete"
         )
+        self.session_id = session_id
         self.result = result