diff --git a/headroom/transforms/content_router.py b/headroom/transforms/content_router.py
index 07e0b880d..8c02c7753 100644
--- a/headroom/transforms/content_router.py
+++ b/headroom/transforms/content_router.py
@@ -1341,6 +1341,9 @@ class ContentRouter(Transform):
                                         f"{decision_reason}_fallback_log_after_no_savings"
                                     )
 
+            # Re-narrow for mypy: all reassignments above produce str, but
+            # mypy 1.14.x widens after nested try/except/else reassignments.
+            assert compressed is not None
             if logger.isEnabledFor(logging.DEBUG):
                 _log_router_debug(
                     "content_router_strategy_result",