diff --git a/tests/agent/test_codex_responses_adapter.py b/tests/agent/test_codex_responses_adapter.py
index 4a14cadf4a3d..cbf2f0e58b61 100644
--- a/tests/agent/test_codex_responses_adapter.py
+++ b/tests/agent/test_codex_responses_adapter.py
@@ -493,14 +493,21 @@ def test_normalize_codex_response_salvage_strips_closing_tag():
 
 
 def test_normalize_codex_response_salvage_is_xai_scoped():
-    """Non-xAI issuers keep the reasoning-only → incomplete classification;
-    the Codex backend replays encrypted reasoning, so its continuation
-    genuinely progresses and must not be short-circuited."""
+    """Non-xAI special-cased issuers (Codex backend) keep the reasoning-only →
+    incomplete classification; the Codex backend replays encrypted reasoning,
+    so its continuation genuinely progresses and must not be short-circuited.
+
+    Pins ``issuer_kind="codex_backend"`` explicitly: with no issuer at all,
+    the unrecognized-backend rule (#64434) trusts ``status="completed"`` and
+    returns ``stop`` — that path is covered by the #64434 regression tests.
+    """
     response = _xai_reasoning_only_response(
         "Thinking.\n<response>The answer.</response>"
     )
 
-    assistant_message, finish_reason = _normalize_codex_response(response)
+    assistant_message, finish_reason = _normalize_codex_response(
+        response, issuer_kind="codex_backend"
+    )
 
     assert finish_reason == "incomplete"
     assert assistant_message.content == ""