diff --git a/codex-rs/core/src/codex.rs b/codex-rs/core/src/codex.rs
index b93bac2287..6695612c9f 100644
--- a/codex-rs/core/src/codex.rs
+++ b/codex-rs/core/src/codex.rs
@@ -2772,6 +2772,18 @@ mod handlers {
         sub_id: String,
         updates: SessionSettingsUpdate,
     ) {
+        let previous_context = sess
+            .new_default_turn_with_sub_id(sess.next_internal_sub_id())
+            .await;
+        let previous_collaboration_mode = sess
+            .state
+            .lock()
+            .await
+            .session_configuration
+            .collaboration_mode
+            .clone();
+        let next_collaboration_mode = updates.collaboration_mode.clone();
+
         if let Err(err) = sess.update_settings(updates).await {
             sess.send_event_raw(Event {
                 id: sub_id,
@@ -2864,6 +2876,14 @@ mod handlers {
             _ => unreachable!(),
         };
 
+        let previous_collaboration_mode = sess
+            .state
+            .lock()
+            .await
+            .session_configuration
+            .collaboration_mode
+            .clone();
+        let next_collaboration_mode = updates.collaboration_mode.clone();
         let Ok(current_context) = sess.new_turn_with_sub_id(sub_id, updates).await else {
             // new_turn_with_sub_id already emits the error event.
             return;