diff --git a/rdagent/app/CI/run.py b/rdagent/app/CI/run.py
index ea02f5be0..8041c5609 100644
--- a/rdagent/app/CI/run.py
+++ b/rdagent/app/CI/run.py
@@ -429,6 +429,10 @@ def evaluate(self, evo: Repo, **kwargs: dict) -> CIFeedback:
 
 
 class CIEvoStr(EvolvingStrategy):
+    def __init__(self) -> None:
+        # CI scenario does not require a Scenario instance
+        self.scen = None
+
     def evolve(  # noqa: C901, PLR0912, PLR0915
         self,
         evo: Repo,