diff --git a/.changeset/dispatcher-plugin-error-code-doc-drift.md b/.changeset/dispatcher-plugin-error-code-doc-drift.md
new file mode 100644
index 0000000000..ef60121515
--- /dev/null
+++ b/.changeset/dispatcher-plugin-error-code-doc-drift.md
@@ -0,0 +1,34 @@
+---
+"@objectstack/runtime": patch
+---
+
+docs(runtime): `errorResponseBase` 文件头不再把 `details.code` 说成线上位置 (#6270)
+
+**纯注释改动，零行为变更。** 没有一行运行时代码被触碰，线上响应体与本次改动前逐字节相同。修的是
+`packages/runtime/src/dispatcher-plugin.ts` 文件头里一句会误导下一个改这个函数的人的话。
+
+原文说：`details.code`（#3842, below）carries `READ_SCOPE_COMPILE_FAILED` **to the
+client** untouched，so **what a machine reads** is unchanged。这两个断言讲的都是**线上位置**，
+而 #5811 之后线上位置不是 `details.code`：`errorResponseBase` 只是把 code **暂存**进一个本地
+`details` 对象，`buildApiError` 随即跑 `splitSemanticCode`，把它**提升**进 `ApiErrorSchema`
+声明的 `error.code` 字段，并把已经空掉的 `details` 返回为 `undefined` —— 于是 `details` 键整个
+从 body 中消失，`error.details.code` 根本不存在可读。实测 500 body 就是：
+
+`{"success":false,"error":{"code":"READ_SCOPE_COMPILE_FAILED","message":"Internal server error","httpStatus":500}}`
+
+这是同一句话漂移的**第四处**。#6123（PR #6264）修了前三处，并明文把 `dispatcher-plugin.ts` 划为
+⛔ 只读参考面，所以第四处按 PD #10 单独立单。措辞刻意与 #6264 在另外三处落的保持一致 —— 这里的价值是
+四处同一句话，而不是第四种独立说法。
+
+危害方向比前三处更陡：前三处的受害者是读 CHANGELOG / 读 `service-analytics` 的人，这一处的受害者
+**就站在做暂存的那个函数里**，读到「details.code carries it to the client」会直接把**本地变量名**
+当成**线上契约**。注释里因此明写了一句 `Do not mistake the local variable name for the wire contract`。
+
+顺带把同一 doc block 里 `:452`-`:457` 那段 JSON 示例的时态钉明确：它展示的是 #5811 **修复之前**的
+泄漏形态（message 原文直接落在 body 里），与新补的当前 body 并排读极易混淆。现在 fence 顶部有一行
+`⚠️ PAST TENSE` 标注并指向 doc block 末尾的当前形态。示例本身**没有删** —— 它记录的是「我们曾经
+泄漏过什么」，是这条 `[#5811]` 条目在做的正经工作。
+
+新措辞的真实性由**既有**测试锚定，本次没有新写断言：
+`packages/runtime/src/analytics-query-read-scope-withhold.test.ts:218` 用真 `AnalyticsService`
+＋真挂载路由断言 `expect(res.body.error.code).toBe('READ_SCOPE_COMPILE_FAILED')`。
diff --git a/packages/runtime/src/dispatcher-plugin.ts b/packages/runtime/src/dispatcher-plugin.ts
index d68830db31..ed829796a7 100644
--- a/packages/runtime/src/dispatcher-plugin.ts
+++ b/packages/runtime/src/dispatcher-plugin.ts
@@ -450,6 +450,8 @@ function sendResultBase(
  * the RLS POLICY the tenant is being filtered by:
  *
  * ```
+ * ⚠️ PAST TENSE — the leak this entry CLOSED, not what this exit answers today.
+ *    For the current body see the corrected shape at the end of this block.
  * POST /analytics/query      (tenant caller, object with a broken sharing rule)
  * → 500 {"success":false,"error":{"message":"[read-scope-sql] unsafe field
  *        identifier \"secret_policy_field\" — refusing to build read scope
@@ -464,9 +466,28 @@ function sendResultBase(
  * boundaries. ⛔ It is NOT "withhold every 5xx" — #5667 kept UNDECLARED 5xx
  * legible on purpose, and a bare `Error` still goes through the heuristic alone.
  *
- * The code still travels: `details.code` (#3842, below) carries
- * `READ_SCOPE_COMPILE_FAILED` to the client untouched, so what a machine reads is
- * unchanged and only the prose is withheld — into `errorReporter` and the log.
+ * The code still travels, and `READ_SCOPE_COMPILE_FAILED` reaches the client
+ * untouched — so what a machine reads is unchanged and only the prose is withheld,
+ * into `errorReporter` and the log.
+ *
+ * ⚠️ It reaches the client at `error.code` — NOT `error.details.code`, which is
+ * where this note pointed until #6270 corrected it (#6123 corrected the same
+ * sentence at three sibling sites). The `details` assembly below (#3842) only
+ * STAGES the code in a local object; `buildApiError` then runs
+ * `splitSemanticCode` (`./error-envelope.ts`), which PROMOTES it into the declared
+ * `ApiErrorSchema` field and returns the now-empty `details` as `undefined` — so
+ * the key is omitted from the body and `error.details.code` is never present to
+ * read. Do not mistake the local variable name for the wire contract. The measured
+ * 500 body is exactly:
+ *
+ * ```json
+ * {"success":false,"error":{"code":"READ_SCOPE_COMPILE_FAILED",
+ *  "message":"Internal server error","httpStatus":500}}
+ * ```
+ *
+ * Pinned end-to-end in `analytics-query-read-scope-withhold.test.ts`, which
+ * asserts the code at `error.code` against a real `AnalyticsService` on a real
+ * mounted route.
  */
 function errorResponseBase(err: any, res: any, securityHeaders?: Record<string, string>): void {
     const validation = validationFailureDetails(err);