diff --git a/codex-rs/core/tests/suite/subagent_notifications.rs b/codex-rs/core/tests/suite/subagent_notifications.rs
index 04ebde856d..85c2347175 100644
--- a/codex-rs/core/tests/suite/subagent_notifications.rs
+++ b/codex-rs/core/tests/suite/subagent_notifications.rs
@@ -144,6 +144,7 @@ async fn setup_turn_one_with_spawned_child(
         server,
         json!({
             "message": CHILD_PROMPT,
+            "fork_context": false,
         }),
         child_response_delay,
         /*wait_for_parent_notification*/ true,