Reset websocket turn state on recon−

codex-rs/core/src/client.rs

@@ -522,6 +522,17 @@ impl ModelClient {
 
     fn set_shared_v2_connection(&self, connection: Option<Arc<ApiWebSocketConnection>>) {
         self.with_shared_v2_state(|state| {
+            let connection_changed = match (&state.connection, &connection) {
+                (Some(existing), Some(new_connection)) => !Arc::ptr_eq(existing, new_connection),
+                (None, Some(_)) | (Some(_), None) => true,
+                (None, None) => false,
+            };
+            if connection_changed {
+                // Response chaining state is scoped to a single backend websocket connection.
+                // When the connection changes, start the next request as a full create.
+                state.websocket_last_items.clear();
+                state.websocket_last_response_id = None;
+            }
             state.connection = connection;
         });
     }

codex-rs/core/tests/suite/turn_state.rs

@@ -221,9 +221,14 @@ async fn websocket_v2_reconnect_after_turn_boundary_does_not_replay_turn_state()
         .first()
         .expect("second websocket connection should have a request")
         .body_json();
-    assert_eq!(
-        second_request["previous_response_id"].as_str(),
-        Some("resp-1")
+    assert_eq!(second_request.get("previous_response_id"), None);
+    let second_input_len = second_request["input"]
+        .as_array()
+        .map(Vec::len)
+        .unwrap_or(0);
+    assert!(
+        second_input_len > 1,
+        "reconnect should send full input items, got {second_input_len}"
     );
 
     server.shutdown().await;