diff --git a/structure/04_transports-and-sidecars.md b/structure/04_transports-and-sidecars.md
index 927a8f2fd5..8c2bb0b7b8 100644
--- a/structure/04_transports-and-sidecars.md
+++ b/structure/04_transports-and-sidecars.md
@@ -44,7 +44,7 @@ Responses-compatible streaming output.
 - 기존 구현 및 제약 조건: The request catalog already controlled custom-tool restoration and the non-OpenAI prompt nudge, but an undeclared upstream name still fell through as an ordinary `function_call`; Codex then reduced the mismatch to a bare `aborted` result.
 - 검토한 주요 대안: Rely only on prompt guidance; automatically translate undeclared `apply_patch` into Code Mode; validate returned names against the request-visible catalog at the final bridge.
 - 선택한 방식: Retain the allowed wire-name set with the existing bridge maps and fail the turn with an explicit compatibility error before emitting any undeclared tool item.
-- 보완된 경계: Key-auth Responses passthrough restores a routed custom call only when the adapter actually lowered that name after request normalization and the caller's `tool_choice` still authorizes it. Native `apply_patch` stays in its upstream function-call form unless the destination explicitly denies Responses custom tools; tools replaced by hosted-provider policy also stay in their upstream function-call form.
+- 보완된 경계: Key-auth Responses passthrough restores a routed custom call only when the adapter actually lowered that name after request normalization and the caller's `tool_choice` still authorizes it. Native `apply_patch` stays in its native custom-tool form unless the destination explicitly denies Responses custom tools; tools replaced by hosted-provider policy also stay in their upstream function-call form.
 - 다른 대안 대신 이 방식을 선택한 이유: Model guidance is not an enforcement boundary, while automatic translation would invent executable caller intent and arguments after generation.
 - 장점, 단점 및 영향: Streaming and non-streaming routed responses now fail closed with an actionable provider-contract error; providers that emit aliases they never advertised must correct their adapter mapping instead of relying on client abort behavior.