docs: 记下 D12 的第一个捕获对象是本仓库自己的测试

e2e 88 的 fixture 声明 `make@4.4` 与 `cmake@3.28`,而索引里是 make 4.3、
cmake 4.4.2/4.0.2 —— 两个版本从来不存在。这条测试在 #531 的整个生命周期里都是绿的,
因为供给不读自己的结果。

⭐ 一般形状:**fixture 里的取值在有东西开始检查它们的那一刻,就不再是随意的了。**
在「这段文字有没有到达那个文件」是唯一断言的时候,它们只是自由字符串。

Author: speak-agent

.agents/docs/2026-08-31-issue540-seven-audit-findings.md

@@ -857,6 +857,22 @@ only ever written for a provisioning that actually succeeded.
 *materialized into* `.xlings.json` — true before #531, and exactly the "declared
 and nothing happened" state the change was made to end.
 
+> **Confirmed harder than predicted, by implementing D12.** That test's fixture
+> declares `deps = ["make@4.4", "cmake@3.28"]`. The index carries make **4.3**
+> and cmake **4.4.2 / 4.0.2** — *neither version has ever existed*. The test
+> passed anyway, for the whole life of #531, because the provisioning did not
+> read its own result: xlings answered `E_NOT_FOUND` and mcpp called it done.
+>
+> So the repository's own most direct coverage of `[xlings] deps` was asserting
+> materialization on top of an install that never happened. D12's first catch,
+> before any user's, was this test. The fixture now names `ninja@1.12.1` —
+> already installed anywhere mcpp can build, so provisioning short-circuits and
+> the test still costs no download.
+>
+> ⭐ The general shape: **a fixture's values stop being arbitrary the moment
+> something starts checking them.** These two were free-form strings for as long
+> as the only assertion was "does this text reach that file".
+
 **D15**, in the order they can be written:
 
 1. **Knob parity, network-free.** `MCPP_NO_AUTO_INSTALL=1` with a declared dep

CHANGELOG.md

@@ -20,7 +20,7 @@
 
 ### 修复
 
-- **`[xlings] deps` 的供给从不检查自己是否成功。** `xlings::call` 返回
+- **`[xlings] deps` 的供给从不检查自己是否成功。**(它的第一个真实受害者是本仓库自己的 e2e 88 —— 见 CHANGELOG 末尾) `xlings::call` 返回
   `expected<CallResult, string>`,只要子进程跑起来就处于**值**态 —— 能力自身的状态
   在 `CallResult` 里面,因为 xlings 讲完 NDJSON 协议后按设计退 0。调用点只测了
   `if (!r)`,于是 xlings 能报出的每一种失败都被读成了成功: