fix(core): attest websocket response handshakes

codex-rs/core/src/client.rs

@@ -830,7 +830,9 @@ impl ModelClient {
         auth_context: AuthRequestTelemetryContext,
         request_route_telemetry: RequestRouteTelemetry,
     ) -> std::result::Result<ApiWebSocketConnection, ApiError> {
-        let headers = self.build_websocket_headers(turn_state.as_ref(), turn_metadata_header);
+        let headers = self
+            .build_websocket_headers(&api_provider, turn_state.as_ref(), turn_metadata_header)
+            .await;
         let websocket_telemetry = ModelClientSession::build_websocket_telemetry(
             session_telemetry,
             auth_context,
@@ -907,8 +909,9 @@ impl ModelClient {
     ///
     /// Callers should pass the current turn-state lock when available so sticky-routing state is
     /// replayed on reconnect within the same turn.
-    fn build_websocket_headers(
+    async fn build_websocket_headers(
         &self,
+        provider: &codex_api::Provider,
         turn_state: Option<&Arc<OnceLock<String>>>,
         turn_metadata_header: Option<&str>,
     ) -> ApiHeaderMap {
@@ -924,6 +927,8 @@ impl ModelClient {
         }
         headers.extend(build_conversation_headers(Some(conversation_id)));
         headers.extend(self.build_responses_identity_headers());
+        self.extend_attestation_header_for(&mut headers, provider, AttestationPurpose::Response)
+            .await;
         headers.insert(
             OPENAI_BETA_HEADER,
             HeaderValue::from_static(RESPONSES_WEBSOCKETS_V2_BETA_HEADER_VALUE),

codex-rs/core/src/client_tests.rs

@@ -562,6 +562,26 @@ async fn responses_generate_fresh_attestation_headers_for_chatgpt_codex() {
     assert_eq!(attestation_calls.load(Ordering::Relaxed), 2);
 }
 
+#[tokio::test]
+async fn websocket_handshake_includes_attestation_for_chatgpt_codex_responses() {
+    let provider = api_provider("https://chatgpt.com/backend-api/codex/");
+    let (model_client, attestation_calls) = model_client_with_counting_attestation();
+
+    let headers = model_client
+        .build_websocket_headers(
+            &provider, /*turn_state*/ None, /*turn_metadata_header*/ None,
+        )
+        .await;
+
+    assert_eq!(
+        headers
+            .get(crate::attestation::X_OAI_ATTESTATION_HEADER)
+            .and_then(|value| value.to_str().ok()),
+        Some("v1.header-1"),
+    );
+    assert_eq!(attestation_calls.load(Ordering::Relaxed), 1);
+}
+
 #[tokio::test]
 async fn compact_generate_fresh_attestation_headers_for_chatgpt_codex() {
     let provider = api_provider("https://chatgpt.com/backend-api/codex/");