diff --git a/codex-rs/app-server/tests/suite/v2/thread_resume.rs b/codex-rs/app-server/tests/suite/v2/thread_resume.rs
index efa51573cb..5eb893b8e1 100644
--- a/codex-rs/app-server/tests/suite/v2/thread_resume.rs
+++ b/codex-rs/app-server/tests/suite/v2/thread_resume.rs
@@ -437,6 +437,14 @@ async fn thread_resume_accepts_personality_override() -> Result<()> {
 
     let request = response_mock.single_request();
     let developer_texts = request.message_input_texts("developer");
+    let personality_update_count = developer_texts
+        .iter()
+        .filter(|text| text.contains("<personality_spec>"))
+        .count();
+    assert_eq!(
+        personality_update_count, 1,
+        "expected exactly one personality update message in developer input, got {developer_texts:?}"
+    );
     assert!(
         developer_texts
             .iter()
diff --git a/codex-rs/app-server/tests/suite/v2/turn_start.rs b/codex-rs/app-server/tests/suite/v2/turn_start.rs
index 1b53a5cfef..35d0c53f85 100644
--- a/codex-rs/app-server/tests/suite/v2/turn_start.rs
+++ b/codex-rs/app-server/tests/suite/v2/turn_start.rs
@@ -474,6 +474,14 @@ async fn turn_start_accepts_personality_override_v2() -> Result<()> {
         eprintln!("request body: {}", request.body_json());
     }
 
+    let personality_update_count = developer_texts
+        .iter()
+        .filter(|text| text.contains("<personality_spec>"))
+        .count();
+    assert_eq!(
+        personality_update_count, 1,
+        "expected exactly one personality update message in developer input, got {developer_texts:?}"
+    );
     assert!(
         developer_texts
             .iter()
@@ -585,6 +593,14 @@ async fn turn_start_change_personality_mid_thread_v2() -> Result<()> {
     );
 
     let second_developer_texts = requests[1].message_input_texts("developer");
+    let personality_update_count = second_developer_texts
+        .iter()
+        .filter(|text| text.contains("<personality_spec>"))
+        .count();
+    assert_eq!(
+        personality_update_count, 1,
+        "expected exactly one personality update message in second request, got {second_developer_texts:?}"
+    );
     assert!(
         second_developer_texts
             .iter()
diff --git a/codex-rs/core/src/codex.rs b/codex-rs/core/src/codex.rs
index 29b02c006a..1ab712ebbf 100644
--- a/codex-rs/core/src/codex.rs
+++ b/codex-rs/core/src/codex.rs
@@ -2434,6 +2434,7 @@ async fn submission_loop(sess: Arc<Session>, config: Arc<Config>, rx_sub: Receiv
                         personality,
                         ..Default::default()
                     },
+                    &mut previous_context,
                 )
                 .await;
             }
@@ -2572,6 +2573,7 @@ mod handlers {
         sess: &Session,
         sub_id: String,
         updates: SessionSettingsUpdate,
+        previous_turn_context: &mut Option<Arc<TurnContext>>,
     ) {
         let previous_context = sess
             .new_default_turn_with_sub_id(sess.next_internal_sub_id())
@@ -2597,12 +2599,13 @@ mod handlers {
             return;
         }
 
+        let current_context = sess.new_default_turn_with_sub_id(sub_id).await;
         let initial_context_seeded = sess.state.lock().await.initial_context_seeded;
         if !initial_context_seeded {
+            *previous_turn_context = Some(current_context);
             return;
         }
 
-        let current_context = sess.new_default_turn_with_sub_id(sub_id).await;
         let update_items = sess.build_settings_update_items(
             Some(&previous_context),
             &current_context,
@@ -2613,6 +2616,7 @@ mod handlers {
             sess.record_conversation_items(&current_context, &update_items)
                 .await;
         }
+        *previous_turn_context = Some(current_context);
     }
 
     pub async fn user_input_or_turn(
diff --git a/codex-rs/core/tests/suite/personality.rs b/codex-rs/core/tests/suite/personality.rs
index 2b00574d58..e3fe3b0d97 100644
--- a/codex-rs/core/tests/suite/personality.rs
+++ b/codex-rs/core/tests/suite/personality.rs
@@ -255,6 +255,14 @@ async fn user_turn_personality_some_adds_update_message() -> anyhow::Result<()>
         .expect("expected personality update request");
 
     let developer_texts = request.message_input_texts("developer");
+    let personality_update_count = developer_texts
+        .iter()
+        .filter(|text| text.contains("<personality_spec>"))
+        .count();
+    assert_eq!(
+        personality_update_count, 1,
+        "expected exactly one personality update message in developer input, got {developer_texts:?}"
+    );
     let personality_text = developer_texts
         .iter()
         .find(|text| text.contains("<personality_spec>"))
@@ -738,6 +746,14 @@ async fn user_turn_personality_remote_model_template_includes_update_message() -
         .last()
         .expect("expected personality update request");
     let developer_texts = request.message_input_texts("developer");
+    let personality_update_count = developer_texts
+        .iter()
+        .filter(|text| text.contains("<personality_spec>"))
+        .count();
+    assert_eq!(
+        personality_update_count, 1,
+        "expected exactly one personality update message in developer input, got {developer_texts:?}"
+    );
     let personality_text = developer_texts
         .iter()
         .find(|text| text.contains("<personality_spec>"))