diff --git a/codex-rs/core/src/thread_manager.rs b/codex-rs/core/src/thread_manager.rs
index ea04ab4708..ecf8bd7c13 100644
--- a/codex-rs/core/src/thread_manager.rs
+++ b/codex-rs/core/src/thread_manager.rs
@@ -918,11 +918,31 @@ fn truncate_before_nth_user_message(
 }
 
 fn snapshot_ends_mid_turn(history: &InitialHistory) -> bool {
+    let rollout_items = history.get_rollout_items();
     let mut builder = ThreadHistoryBuilder::new();
-    for item in history.get_rollout_items() {
-        builder.handle_rollout_item(&item);
+    for item in &rollout_items {
+        builder.handle_rollout_item(item);
     }
-    builder.has_active_turn()
+    if builder.has_active_turn() {
+        return true;
+    }
+
+    let Some(last_user_position) = truncation::user_message_positions_in_rollout(&rollout_items)
+        .last()
+        .copied()
+    else {
+        return false;
+    };
+
+    // Synthetic fork/resume histories can contain user/assistant response items
+    // without explicit turn lifecycle events. If the persisted snapshot has no
+    // terminating boundary after its last user message, treat it as mid-turn.
+    !rollout_items[last_user_position + 1..].iter().any(|item| {
+        matches!(
+            item,
+            RolloutItem::EventMsg(EventMsg::TurnComplete(_) | EventMsg::TurnAborted(_))
+        )
+    })
 }
 
 /// Append the same model-visible interruption marker used by the live interrupt
diff --git a/codex-rs/core/src/thread_manager_tests.rs b/codex-rs/core/src/thread_manager_tests.rs
index 52e56e0549..2bc572ab6a 100644
--- a/codex-rs/core/src/thread_manager_tests.rs
+++ b/codex-rs/core/src/thread_manager_tests.rs
@@ -310,10 +310,9 @@ async fn interrupted_fork_snapshot_uses_persisted_mid_turn_history_without_live_
         .into_iter()
         .filter(|item| !matches!(item, RolloutItem::SessionMeta(_)))
         .collect();
-    let interrupted_marker_json = serde_json::to_value(RolloutItem::ResponseItem(
-        interrupted_turn_history_marker(),
-    ))
-    .expect("serialize interrupted marker");
+    let interrupted_marker_json =
+        serde_json::to_value(RolloutItem::ResponseItem(interrupted_turn_history_marker()))
+            .expect("serialize interrupted marker");
     assert_eq!(
         forked_rollout_items
             .iter()