diff --git a/README.md b/README.md
index b6e7373..0e68c13 100644
--- a/README.md
+++ b/README.md
@@ -123,6 +123,10 @@ docker compose logs --tail=200 runtime caddy
 docker compose exec runtime pnpm --filter @sammo-ts/release-controller status
 ```
 
+Caddy의 runtime logger는 reverse proxy 오류에도 요청 정보를 남길 수 있으므로
+`X-Session-Token` 값을 encoder 단계에서 삭제합니다. 장애 로그를 수집할 때도
+인증 헤더, cookie, token과 secret을 보고서나 채팅에 복사하지 않습니다.
+
 ## 개발 bind 모드
 
 로컬 Core2026 checkout을 container에 bind하고 DB/Redis/Caddy는 같은 구성으로
diff --git a/caddy/Caddyfile b/caddy/Caddyfile
index b4ba1a9..3cb2a9d 100644
--- a/caddy/Caddyfile
+++ b/caddy/Caddyfile
@@ -1,5 +1,10 @@
 {
 	email {$ACME_EMAIL}
+	log {
+		format filter {
+			request>headers>X-Session-Token delete
+		}
+	}
 }
 
 {$SITE_ADDRESS} {
diff --git a/test/runtime-secret-boundary.test.mjs b/test/runtime-secret-boundary.test.mjs
index 5d51bd8..156004c 100644
--- a/test/runtime-secret-boundary.test.mjs
+++ b/test/runtime-secret-boundary.test.mjs
@@ -38,3 +38,9 @@ test('runtime entrypoint removes raw repository secrets before launching PM2', a
   assert.ok(httpsUnset > 0 && httpsUnset < pm2Start);
   assert.ok(sshUnset > 0 && sshUnset < pm2Start);
 });
+
+test('Caddy runtime logs remove the custom Gateway session header', async () => {
+  const caddyfile = await fs.readFile(new URL('../caddy/Caddyfile', import.meta.url), 'utf8');
+
+  assert.match(caddyfile, /log\s*\{[\s\S]*format filter\s*\{[\s\S]*request>headers>X-Session-Token delete/);
+});