diff --git a/codex-rs/core/src/codex_thread.rs b/codex-rs/core/src/codex_thread.rs
index 7b57bd74e5..b2df5cde07 100644
--- a/codex-rs/core/src/codex_thread.rs
+++ b/codex-rs/core/src/codex_thread.rs
@@ -593,6 +593,20 @@ impl CodexThread {
 
     /// Record raw Responses API items without starting a new turn.
     pub async fn inject_response_items(&self, items: Vec<ResponseItem>) -> CodexResult<()> {
+        self.inject_response_items_for_turn(items).await?;
+        self.session.flush_rollout().await?;
+        Ok(())
+    }
+
+    /// Record raw Responses API items immediately before admitting a user turn.
+    ///
+    /// The caller must submit the associated user input while retaining its
+    /// thread-operation lock. The subsequent turn persistence includes both
+    /// these items and the user input, without an independent rollout flush.
+    pub async fn inject_response_items_for_turn(
+        &self,
+        items: Vec<ResponseItem>,
+    ) -> CodexResult<()> {
         if items.is_empty() {
             return Err(CodexErr::InvalidRequest(
                 "items must not be empty".to_string(),
@@ -613,7 +627,6 @@ impl CodexThread {
         self.session
             .inject_no_new_turn(items, Some(turn_context.as_ref()))
             .await;
-        self.session.flush_rollout().await?;
         Ok(())
     }
 
diff --git a/codex-rs/core/tests/suite/user_message_admission.rs b/codex-rs/core/tests/suite/user_message_admission.rs
index b3f3c7d8b7..e89c9ba6fb 100644
--- a/codex-rs/core/tests/suite/user_message_admission.rs
+++ b/codex-rs/core/tests/suite/user_message_admission.rs
@@ -54,7 +54,7 @@ async fn default_turn_start_persists_developer_and_user_input_before_model_reque
         .await
         .expect("build default thread-store session");
     test.codex
-        .inject_response_items(vec![ResponseItem::Message {
+        .inject_response_items_for_turn(vec![ResponseItem::Message {
             id: None,
             role: "developer".to_string(),
             content: vec![ContentItem::InputText {