diff --git a/scripts/check/check-env-doc-sync.mjs b/scripts/check/check-env-doc-sync.mjs
index 469a2bfabb..2f5d0b790f 100644
--- a/scripts/check/check-env-doc-sync.mjs
+++ b/scripts/check/check-env-doc-sync.mjs
@@ -283,6 +283,8 @@ const ENV_ONLY_ALLOWLIST = new Set([
   "PII_WINDOW_SIZE",
   "TRAE_STREAM_TIMEOUT_MS",
   "TRAE_TOKEN",
+  // #12190: Trae host/Origin override. ENVIRONMENT.md documents no Trae variable at
+  // all; this joins its two siblings above under the same .env.example-only tier.
   "TRAE_WEB_ORIGIN",
 ]);