diff --git a/CHANGELOG.md b/CHANGELOG.md
index 38c9f568..4db9fb95 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,6 +9,15 @@
 
 ### Added
 
+- **`openkal` 0.16.0 及随之移动的七个包。** 规范新增 `kal_task_start_sized`(栈大小的下限,
+  给不出时为 `kal_err_no_memory`)与 `KAL_TERM_PASS_INPUT`(环境不改写所输入的字节),
+  并补述关闭目录即结束其未读完的枚举。`openkal-linux` 0.17.0、`openkal-macos` 0.14.0、
+  `openkal-windows` 0.12.0、`openkal-emscripten` 0.5.0 实现三者;`openkal-opensbi` 0.8.3
+  只移动规范的锁定版本;`openkal-musl` 0.21.0 让线程得到所请求的栈并在 raw 模式下区分
+  回车与 Ctrl+J;`openkal-llvm-runtime` 0.15.5 移动 C 库的锁定版本。GLOBAL 为上游 tag 归档,
+  CN 为逐字节相同的 gitcode 资源,均按记录的 sha256 核对。
+  新增两个测试成员:`tests/examples/openkal`(规范在三平台、各实现在自身平台,以及新声明的 C
+  层行为)与 `tests/examples/openkal-musl`(三份报告的原始程序,Linux)。
 - **`compat.httplib` 0.62.0。** 在 `0.53.1` 之外新增版本键(旧键保留)。仍是纯头文件 Form B:
   归档根目录仍只有一份 `httplib.h`(747,115 → 846,648 字节,增量是 SSE 客户端、WebSocket
   辅助与加固,全部落在头内,不引入 define、源文件或链接依赖),描述符的内联构建无需改动。
@@ -182,6 +191,12 @@
 
 ### Changed
 
+- **候选门只在消费者构建候选包的平台上调度它。** `tests/autoupdate/ci.py` 的
+  `member_platforms` 读取消费者清单:无条件依赖在三个平台调度;`cfg(os = ...)` 或
+  `cfg(windows)` 下的依赖只在该平台调度;其余条件(环境、架构)不调度任何宿主作业,由包自身仓库
+  在目标上测量。mcpp 只锁定宿主解析到的包,向另一平台的 runner 要平台包的锁定证明必然失败;
+  `test_ci.py` 覆盖了这条规则。
+
 - **站点的 openkal 分面改为两个取值:`openkal-ecosystem` 与 `openkal-compat`。** 原先的
   「openkal itself / runs on openkal / fails on openkal」是句子而不是名字。构成 openkal 的
   包归入 `openkal-ecosystem`;测试项目在 openkal 依赖图中测得 `runs` 的包归入
diff --git a/mcpp.toml b/mcpp.toml
index 9d9ea35e..a4ed5bb0 100644
--- a/mcpp.toml
+++ b/mcpp.toml
@@ -206,6 +206,8 @@ members = [
     "tests/examples/quickjs-ng",
     "tests/examples/rapidcsv",
     "tests/examples/mcr",
+    "tests/examples/openkal",
+    "tests/examples/openkal-musl",
 ]
 
 # ── The index redirect, hoisted to the workspace root ───────────────────
diff --git a/pkgs/o/openkal-emscripten.lua b/pkgs/o/openkal-emscripten.lua
index e1283052..bb0719b9 100644
--- a/pkgs/o/openkal-emscripten.lua
+++ b/pkgs/o/openkal-emscripten.lua
@@ -45,6 +45,13 @@ package = {
 
     xpm = {
         linux = {
+            ["0.5.0"] = {
+                url    = {
+                    GLOBAL = "https://github.com/mcpplibs/openkal-emscripten/archive/refs/tags/0.5.0.tar.gz",
+                    CN     = "https://gitcode.com/mcpp-res/openkal-emscripten/releases/download/0.5.0/openkal-emscripten-0.5.0.tar.gz",
+                },
+                sha256 = "3f6ad34e6da89cd41899965a25083200b52eb2b36cc3ff138f82cb018638a217",
+            },
             ["0.4.0"] = {
                 url    = {
                     GLOBAL = "https://github.com/mcpplibs/openkal-emscripten/archive/refs/tags/0.4.0.tar.gz",
@@ -89,6 +96,13 @@ package = {
             },
         },
         macosx = {
+            ["0.5.0"] = {
+                url    = {
+                    GLOBAL = "https://github.com/mcpplibs/openkal-emscripten/archive/refs/tags/0.5.0.tar.gz",
+                    CN     = "https://gitcode.com/mcpp-res/openkal-emscripten/releases/download/0.5.0/openkal-emscripten-0.5.0.tar.gz",
+                },
+                sha256 = "3f6ad34e6da89cd41899965a25083200b52eb2b36cc3ff138f82cb018638a217",
+            },
             ["0.4.0"] = {
                 url    = {
                     GLOBAL = "https://github.com/mcpplibs/openkal-emscripten/archive/refs/tags/0.4.0.tar.gz",
@@ -133,6 +147,13 @@ package = {
             },
         },
         windows = {
+            ["0.5.0"] = {
+                url    = {
+                    GLOBAL = "https://github.com/mcpplibs/openkal-emscripten/archive/refs/tags/0.5.0.tar.gz",
+                    CN     = "https://gitcode.com/mcpp-res/openkal-emscripten/releases/download/0.5.0/openkal-emscripten-0.5.0.tar.gz",
+                },
+                sha256 = "3f6ad34e6da89cd41899965a25083200b52eb2b36cc3ff138f82cb018638a217",
+            },
             ["0.4.0"] = {
                 url    = {
                     GLOBAL = "https://github.com/mcpplibs/openkal-emscripten/archive/refs/tags/0.4.0.tar.gz",
diff --git a/pkgs/o/openkal-linux.lua b/pkgs/o/openkal-linux.lua
index 860171a6..bdefb0c1 100644
--- a/pkgs/o/openkal-linux.lua
+++ b/pkgs/o/openkal-linux.lua
@@ -19,6 +19,13 @@ package = {
 
     xpm = {
         linux = {
+            ["0.17.0"] = {
+                url    = {
+                    GLOBAL = "https://github.com/mcpplibs/openkal-linux/archive/refs/tags/0.17.0.tar.gz",
+                    CN     = "https://gitcode.com/mcpp-res/openkal-linux/releases/download/0.17.0/openkal-linux-0.17.0.tar.gz",
+                },
+                sha256 = "fc815721f0cb4fddcc708cf7960fe1d06f40d2c9541eeaaf3858bb9f53fadbe9",
+            },
             ["0.16.1"] = {
                 url    = {
                     GLOBAL = "https://github.com/mcpplibs/openkal-linux/archive/refs/tags/0.16.1.tar.gz",
@@ -147,6 +154,13 @@ package = {
             },
         },
         macosx = {
+            ["0.17.0"] = {
+                url    = {
+                    GLOBAL = "https://github.com/mcpplibs/openkal-linux/archive/refs/tags/0.17.0.tar.gz",
+                    CN     = "https://gitcode.com/mcpp-res/openkal-linux/releases/download/0.17.0/openkal-linux-0.17.0.tar.gz",
+                },
+                sha256 = "fc815721f0cb4fddcc708cf7960fe1d06f40d2c9541eeaaf3858bb9f53fadbe9",
+            },
             ["0.16.1"] = {
                 url    = {
                     GLOBAL = "https://github.com/mcpplibs/openkal-linux/archive/refs/tags/0.16.1.tar.gz",
@@ -275,6 +289,13 @@ package = {
             },
         },
         windows = {
+            ["0.17.0"] = {
+                url    = {
+                    GLOBAL = "https://github.com/mcpplibs/openkal-linux/archive/refs/tags/0.17.0.tar.gz",
+                    CN     = "https://gitcode.com/mcpp-res/openkal-linux/releases/download/0.17.0/openkal-linux-0.17.0.tar.gz",
+                },
+                sha256 = "fc815721f0cb4fddcc708cf7960fe1d06f40d2c9541eeaaf3858bb9f53fadbe9",
+            },
             ["0.16.1"] = {
                 url    = {
                     GLOBAL = "https://github.com/mcpplibs/openkal-linux/archive/refs/tags/0.16.1.tar.gz",
diff --git a/pkgs/o/openkal-llvm-runtime.lua b/pkgs/o/openkal-llvm-runtime.lua
index f9fa2de9..970c9b3a 100644
--- a/pkgs/o/openkal-llvm-runtime.lua
+++ b/pkgs/o/openkal-llvm-runtime.lua
@@ -75,6 +75,13 @@ package = {
 
     xpm = {
         linux = {
+            ["0.15.5"] = {
+                url    = {
+                    GLOBAL = "https://github.com/mcpplibs/openkal-llvm-runtime/archive/refs/tags/0.15.5.tar.gz",
+                    CN     = "https://gitcode.com/mcpp-res/openkal-llvm-runtime/releases/download/0.15.5/openkal-llvm-runtime-0.15.5.tar.gz",
+                },
+                sha256 = "22adf246d2a0cbf2083d09d88329c475f6c1976ea69d0d6cc0391b129fde12ae",
+            },
             ["0.15.4"] = {
                 url    = {
                     GLOBAL = "https://github.com/mcpplibs/openkal-llvm-runtime/archive/refs/tags/0.15.4.tar.gz",
@@ -287,6 +294,13 @@ package = {
             },
         },
         macosx = {
+            ["0.15.5"] = {
+                url    = {
+                    GLOBAL = "https://github.com/mcpplibs/openkal-llvm-runtime/archive/refs/tags/0.15.5.tar.gz",
+                    CN     = "https://gitcode.com/mcpp-res/openkal-llvm-runtime/releases/download/0.15.5/openkal-llvm-runtime-0.15.5.tar.gz",
+                },
+                sha256 = "22adf246d2a0cbf2083d09d88329c475f6c1976ea69d0d6cc0391b129fde12ae",
+            },
             ["0.15.4"] = {
                 url    = {
                     GLOBAL = "https://github.com/mcpplibs/openkal-llvm-runtime/archive/refs/tags/0.15.4.tar.gz",
@@ -499,6 +513,13 @@ package = {
             },
         },
         windows = {
+            ["0.15.5"] = {
+                url    = {
+                    GLOBAL = "https://github.com/mcpplibs/openkal-llvm-runtime/archive/refs/tags/0.15.5.tar.gz",
+                    CN     = "https://gitcode.com/mcpp-res/openkal-llvm-runtime/releases/download/0.15.5/openkal-llvm-runtime-0.15.5.tar.gz",
+                },
+                sha256 = "22adf246d2a0cbf2083d09d88329c475f6c1976ea69d0d6cc0391b129fde12ae",
+            },
             ["0.15.4"] = {
                 url    = {
                     GLOBAL = "https://github.com/mcpplibs/openkal-llvm-runtime/archive/refs/tags/0.15.4.tar.gz",
diff --git a/pkgs/o/openkal-macos.lua b/pkgs/o/openkal-macos.lua
index 52c81350..01d2da08 100644
--- a/pkgs/o/openkal-macos.lua
+++ b/pkgs/o/openkal-macos.lua
@@ -19,6 +19,13 @@ package = {
 
     xpm = {
         linux = {
+            ["0.14.0"] = {
+                url    = {
+                    GLOBAL = "https://github.com/mcpplibs/openkal-macos/archive/refs/tags/0.14.0.tar.gz",
+                    CN     = "https://gitcode.com/mcpp-res/openkal-macos/releases/download/0.14.0/openkal-macos-0.14.0.tar.gz",
+                },
+                sha256 = "823fa17180c161831dbf4e68bb128738b955d6d4228b22c3bd75e0b826a31a9f",
+            },
             ["0.13.0"] = {
                 url    = {
                     GLOBAL = "https://github.com/mcpplibs/openkal-macos/archive/refs/tags/0.13.0.tar.gz",
@@ -147,6 +154,13 @@ package = {
             },
         },
         macosx = {
+            ["0.14.0"] = {
+                url    = {
+                    GLOBAL = "https://github.com/mcpplibs/openkal-macos/archive/refs/tags/0.14.0.tar.gz",
+                    CN     = "https://gitcode.com/mcpp-res/openkal-macos/releases/download/0.14.0/openkal-macos-0.14.0.tar.gz",
+                },
+                sha256 = "823fa17180c161831dbf4e68bb128738b955d6d4228b22c3bd75e0b826a31a9f",
+            },
             ["0.13.0"] = {
                 url    = {
                     GLOBAL = "https://github.com/mcpplibs/openkal-macos/archive/refs/tags/0.13.0.tar.gz",
@@ -275,6 +289,13 @@ package = {
             },
         },
         windows = {
+            ["0.14.0"] = {
+                url    = {
+                    GLOBAL = "https://github.com/mcpplibs/openkal-macos/archive/refs/tags/0.14.0.tar.gz",
+                    CN     = "https://gitcode.com/mcpp-res/openkal-macos/releases/download/0.14.0/openkal-macos-0.14.0.tar.gz",
+                },
+                sha256 = "823fa17180c161831dbf4e68bb128738b955d6d4228b22c3bd75e0b826a31a9f",
+            },
             ["0.13.0"] = {
                 url    = {
                     GLOBAL = "https://github.com/mcpplibs/openkal-macos/archive/refs/tags/0.13.0.tar.gz",
diff --git a/pkgs/o/openkal-musl.lua b/pkgs/o/openkal-musl.lua
index 01b7e85f..6dc75fa7 100644
--- a/pkgs/o/openkal-musl.lua
+++ b/pkgs/o/openkal-musl.lua
@@ -64,6 +64,13 @@ package = {
 
     xpm = {
         linux = {
+            ["0.21.0"] = {
+                url    = {
+                    GLOBAL = "https://github.com/mcpplibs/openkal-musl/archive/refs/tags/0.21.0.tar.gz",
+                    CN     = "https://gitcode.com/mcpp-res/openkal-musl/releases/download/0.21.0/openkal-musl-0.21.0.tar.gz",
+                },
+                sha256 = "98889c1fa7bbac05787e8c362ea79e4941c97aaa1ffca86a0ed7d88ff419545c",
+            },
             ["0.20.1"] = {
                 url    = {
                     GLOBAL = "https://github.com/mcpplibs/openkal-musl/archive/refs/tags/0.20.1.tar.gz",
@@ -290,6 +297,13 @@ package = {
             },
         },
         macosx = {
+            ["0.21.0"] = {
+                url    = {
+                    GLOBAL = "https://github.com/mcpplibs/openkal-musl/archive/refs/tags/0.21.0.tar.gz",
+                    CN     = "https://gitcode.com/mcpp-res/openkal-musl/releases/download/0.21.0/openkal-musl-0.21.0.tar.gz",
+                },
+                sha256 = "98889c1fa7bbac05787e8c362ea79e4941c97aaa1ffca86a0ed7d88ff419545c",
+            },
             ["0.20.1"] = {
                 url    = {
                     GLOBAL = "https://github.com/mcpplibs/openkal-musl/archive/refs/tags/0.20.1.tar.gz",
@@ -516,6 +530,13 @@ package = {
             },
         },
         windows = {
+            ["0.21.0"] = {
+                url    = {
+                    GLOBAL = "https://github.com/mcpplibs/openkal-musl/archive/refs/tags/0.21.0.tar.gz",
+                    CN     = "https://gitcode.com/mcpp-res/openkal-musl/releases/download/0.21.0/openkal-musl-0.21.0.tar.gz",
+                },
+                sha256 = "98889c1fa7bbac05787e8c362ea79e4941c97aaa1ffca86a0ed7d88ff419545c",
+            },
             ["0.20.1"] = {
                 url    = {
                     GLOBAL = "https://github.com/mcpplibs/openkal-musl/archive/refs/tags/0.20.1.tar.gz",
diff --git a/pkgs/o/openkal-opensbi.lua b/pkgs/o/openkal-opensbi.lua
index accdb069..419f1363 100644
--- a/pkgs/o/openkal-opensbi.lua
+++ b/pkgs/o/openkal-opensbi.lua
@@ -20,6 +20,13 @@ package = {
 
     xpm = {
         linux = {
+            ["0.8.3"] = {
+                url    = {
+                    GLOBAL = "https://github.com/mcpplibs/openkal-opensbi/archive/refs/tags/0.8.3.tar.gz",
+                    CN     = "https://gitcode.com/mcpp-res/openkal-opensbi/releases/download/0.8.3/openkal-opensbi-0.8.3.tar.gz",
+                },
+                sha256 = "d585a8e614b27e7cd992f4db53fba200440f164870e9f475f67e976ff090aae3",
+            },
             ["0.8.2"] = {
                 url    = {
                     GLOBAL = "https://github.com/mcpplibs/openkal-opensbi/archive/refs/tags/0.8.2.tar.gz",
@@ -120,6 +127,13 @@ package = {
             },
         },
         macosx = {
+            ["0.8.3"] = {
+                url    = {
+                    GLOBAL = "https://github.com/mcpplibs/openkal-opensbi/archive/refs/tags/0.8.3.tar.gz",
+                    CN     = "https://gitcode.com/mcpp-res/openkal-opensbi/releases/download/0.8.3/openkal-opensbi-0.8.3.tar.gz",
+                },
+                sha256 = "d585a8e614b27e7cd992f4db53fba200440f164870e9f475f67e976ff090aae3",
+            },
             ["0.8.2"] = {
                 url    = {
                     GLOBAL = "https://github.com/mcpplibs/openkal-opensbi/archive/refs/tags/0.8.2.tar.gz",
@@ -220,6 +234,13 @@ package = {
             },
         },
         windows = {
+            ["0.8.3"] = {
+                url    = {
+                    GLOBAL = "https://github.com/mcpplibs/openkal-opensbi/archive/refs/tags/0.8.3.tar.gz",
+                    CN     = "https://gitcode.com/mcpp-res/openkal-opensbi/releases/download/0.8.3/openkal-opensbi-0.8.3.tar.gz",
+                },
+                sha256 = "d585a8e614b27e7cd992f4db53fba200440f164870e9f475f67e976ff090aae3",
+            },
             ["0.8.2"] = {
                 url    = {
                     GLOBAL = "https://github.com/mcpplibs/openkal-opensbi/archive/refs/tags/0.8.2.tar.gz",
diff --git a/pkgs/o/openkal-windows.lua b/pkgs/o/openkal-windows.lua
index e32e13e8..aee05089 100644
--- a/pkgs/o/openkal-windows.lua
+++ b/pkgs/o/openkal-windows.lua
@@ -21,6 +21,13 @@ package = {
 
     xpm = {
         linux = {
+            ["0.12.0"] = {
+                url    = {
+                    GLOBAL = "https://github.com/mcpplibs/openkal-windows/archive/refs/tags/0.12.0.tar.gz",
+                    CN     = "https://gitcode.com/mcpp-res/openkal-windows/releases/download/0.12.0/openkal-windows-0.12.0.tar.gz",
+                },
+                sha256 = "5ba523c3c34a0fe2257716bab3ce5196b38b98468283e93cc90b26feb65f6d46",
+            },
             ["0.11.0"] = {
                 url    = {
                     GLOBAL = "https://github.com/mcpplibs/openkal-windows/archive/refs/tags/0.11.0.tar.gz",
@@ -170,6 +177,13 @@ package = {
             },
         },
         macosx = {
+            ["0.12.0"] = {
+                url    = {
+                    GLOBAL = "https://github.com/mcpplibs/openkal-windows/archive/refs/tags/0.12.0.tar.gz",
+                    CN     = "https://gitcode.com/mcpp-res/openkal-windows/releases/download/0.12.0/openkal-windows-0.12.0.tar.gz",
+                },
+                sha256 = "5ba523c3c34a0fe2257716bab3ce5196b38b98468283e93cc90b26feb65f6d46",
+            },
             ["0.11.0"] = {
                 url    = {
                     GLOBAL = "https://github.com/mcpplibs/openkal-windows/archive/refs/tags/0.11.0.tar.gz",
@@ -319,6 +333,13 @@ package = {
             },
         },
         windows = {
+            ["0.12.0"] = {
+                url    = {
+                    GLOBAL = "https://github.com/mcpplibs/openkal-windows/archive/refs/tags/0.12.0.tar.gz",
+                    CN     = "https://gitcode.com/mcpp-res/openkal-windows/releases/download/0.12.0/openkal-windows-0.12.0.tar.gz",
+                },
+                sha256 = "5ba523c3c34a0fe2257716bab3ce5196b38b98468283e93cc90b26feb65f6d46",
+            },
             ["0.11.0"] = {
                 url    = {
                     GLOBAL = "https://github.com/mcpplibs/openkal-windows/archive/refs/tags/0.11.0.tar.gz",
diff --git a/pkgs/o/openkal.lua b/pkgs/o/openkal.lua
index ac39fccd..b20717af 100644
--- a/pkgs/o/openkal.lua
+++ b/pkgs/o/openkal.lua
@@ -22,6 +22,13 @@ package = {
 
     xpm = {
         linux = {
+            ["0.16.0"] = {
+                url    = {
+                    GLOBAL = "https://github.com/mcpplibs/openkal/archive/refs/tags/0.16.0.tar.gz",
+                    CN     = "https://gitcode.com/mcpp-res/openkal/releases/download/0.16.0/openkal-0.16.0.tar.gz",
+                },
+                sha256 = "24a349b4eb7cd3d916455a8700718d57ee7ecce5cc161800f4842dece414e034",
+            },
             ["0.15.0"] = {
                 url    = {
                     GLOBAL = "https://github.com/mcpplibs/openkal/archive/refs/tags/0.15.0.tar.gz",
@@ -122,6 +129,13 @@ package = {
             },
         },
         macosx = {
+            ["0.16.0"] = {
+                url    = {
+                    GLOBAL = "https://github.com/mcpplibs/openkal/archive/refs/tags/0.16.0.tar.gz",
+                    CN     = "https://gitcode.com/mcpp-res/openkal/releases/download/0.16.0/openkal-0.16.0.tar.gz",
+                },
+                sha256 = "24a349b4eb7cd3d916455a8700718d57ee7ecce5cc161800f4842dece414e034",
+            },
             ["0.15.0"] = {
                 url    = {
                     GLOBAL = "https://github.com/mcpplibs/openkal/archive/refs/tags/0.15.0.tar.gz",
@@ -222,6 +236,13 @@ package = {
             },
         },
         windows = {
+            ["0.16.0"] = {
+                url    = {
+                    GLOBAL = "https://github.com/mcpplibs/openkal/archive/refs/tags/0.16.0.tar.gz",
+                    CN     = "https://gitcode.com/mcpp-res/openkal/releases/download/0.16.0/openkal-0.16.0.tar.gz",
+                },
+                sha256 = "24a349b4eb7cd3d916455a8700718d57ee7ecce5cc161800f4842dece414e034",
+            },
             ["0.15.0"] = {
                 url    = {
                     GLOBAL = "https://github.com/mcpplibs/openkal/archive/refs/tags/0.15.0.tar.gz",
diff --git a/tests/autoupdate/ci.py b/tests/autoupdate/ci.py
index 5ac9b733..a81c81cf 100644
--- a/tests/autoupdate/ci.py
+++ b/tests/autoupdate/ci.py
@@ -101,6 +101,38 @@ def direct_member(identity: str) -> str | None:
     return min(candidates, key=lambda value: (len(value), value))
 
 
+# The runner platforms, by the spelling a member's `cfg(os = ...)` uses.
+_CFG_PLATFORMS = {"linux": "linux", "macos": "macosx", "windows": "windows"}
+
+
+def member_platforms(member: str, identity: str) -> set[str]:
+    """The runner platforms on which `member` builds `identity`.
+
+    A member that names the package unconditionally builds it everywhere. One
+    that names it under `[target.'cfg(...)']` builds it only where the condition
+    holds, and a lockfile proves a candidate only where it was built: mcpp locks
+    what the host resolves, so a platform package asked of another platform's
+    runner is a job that can only fail. A condition naming one operating system
+    (`os = "linux"`, `os = "macos"`, `windows`) selects that runner; any other
+    condition (an environment, an architecture, a family) selects none, because
+    no runner here builds for it and the package is measured by its own
+    repository on that target.
+    """
+    namespace, name = identity.split(":", 1)
+    manifest = tomllib.loads((ROOT / "tests/examples" / member / "mcpp.toml").read_text(encoding="utf-8"))
+    platforms: set[str] = set()
+    if name in manifest.get("dependencies", {}).get(namespace, {}):
+        platforms |= set(_CFG_PLATFORMS.values())
+    for condition, table in manifest.get("target", {}).items():
+        if name not in table.get("dependencies", {}).get(namespace, {}):
+            continue
+        spelled = re.fullmatch(r'cfg\(\s*(?:os\s*=\s*"(\w+)"|(windows))\s*\)', condition.strip())
+        if spelled:
+            platforms.add(_CFG_PLATFORMS.get(spelled.group(1) or spelled.group(2), ""))
+    platforms.discard("")
+    return platforms
+
+
 def matrix(plan: Path, output: Path, base: str):
     build_plan = json.loads(plan.read_text(encoding="utf-8"))
     # A normal bump PR already contains its candidate, so discovery says up-to-date.
@@ -136,7 +168,13 @@ def matrix(plan: Path, output: Path, base: str):
         member = direct_member(record["id"])
         if member is None and record["id"] not in ("compat:hiredis", "compat:libuv"):
             raise RuntimeError(f"no candidate consumer: {record['id']}")
+        applicable = member_platforms(member, record["id"]) if member else None
+        if applicable is not None and not applicable:
+            print(f"{record['id']}: {member} names it only for a target no runner builds; "
+                  "measured by its own repository on that target")
         for platform in [asset["platform"] for asset in record["assets"]]:
+            if applicable is not None and platform not in applicable:
+                continue
             rows = {
                 "linux": ("ubuntu-latest", "linux-x86_64", "tar.gz"),
                 "macosx": ("macos-15", "macosx-arm64", "tar.gz"),
diff --git a/tests/autoupdate/test_ci.py b/tests/autoupdate/test_ci.py
index 0b8da9e2..c837f69b 100644
--- a/tests/autoupdate/test_ci.py
+++ b/tests/autoupdate/test_ci.py
@@ -100,3 +100,42 @@ def test_revision_allows_packaging_fix_but_not_resource_drift(self):
                     'sha256 = "' + "a" * 64 + '",\n   revision = 0,'))
                 with self.assertRaisesRegex(RuntimeError, "revision decreased"):
                     ci.audit("HEAD", root / "coverage.json")
+
+
+class MemberPlatformTests(unittest.TestCase):
+    """A candidate is asked of the runners its consumer builds it on, and of no other."""
+
+    def member(self, root, text):
+        member = root / "tests/examples/probe"
+        member.mkdir(parents=True)
+        (member / "mcpp.toml").write_text(text, encoding="utf-8")
+
+    def test_conditions_select_runners(self):
+        with tempfile.TemporaryDirectory() as directory:
+            root = Path(directory)
+            self.member(root, """[package]
+name = "probe"
+version = "0.1.0"
+
+[dependencies.acme]
+spec = "1.0.0"
+
+[target.'cfg(os = "linux")'.dependencies.acme]
+on-linux = "1.0.0"
+
+[target.'cfg(os = "macos")'.dependencies.acme]
+on-macos = "1.0.0"
+
+[target.'cfg(windows)'.dependencies.acme]
+on-windows = "1.0.0"
+
+[target.'cfg(all(os = "linux", env = "musl"))'.dependencies.acme]
+on-musl = "1.0.0"
+""")
+            with patch.object(ci, "ROOT", root):
+                self.assertEqual(ci.member_platforms("probe", "acme:spec"), {"linux", "macosx", "windows"})
+                self.assertEqual(ci.member_platforms("probe", "acme:on-linux"), {"linux"})
+                self.assertEqual(ci.member_platforms("probe", "acme:on-macos"), {"macosx"})
+                self.assertEqual(ci.member_platforms("probe", "acme:on-windows"), {"windows"})
+                self.assertEqual(ci.member_platforms("probe", "acme:on-musl"), set())
+                self.assertEqual(ci.member_platforms("probe", "other:spec"), set())
diff --git a/tests/examples/openkal-musl/mcpp.toml b/tests/examples/openkal-musl/mcpp.toml
new file mode 100644
index 00000000..7969a47f
--- /dev/null
+++ b/tests/examples/openkal-musl/mcpp.toml
@@ -0,0 +1,22 @@
+# openkal-musl test project: a C program whose C library is musl redirected
+# onto openkal, running the programs three reports were written with
+# (mcpplibs/openkal-linux#34, mcpplibs/openkal-musl#48, the stack and the
+# supplied stack). Linux only: the port's other systems are measured by its
+# own repository, and the candidate gate asks this member nothing elsewhere.
+[package]
+name    = "openkal-musl-tests"
+version = "0.1.0"
+
+[target.'cfg(os = "linux")'.dependencies.mcpplibs]
+openkal-musl = "0.21.0"
+
+[target.'cfg(os = "linux")'.build]
+cxxflags = ["-DHAVE_OPENKAL_MUSL=1"]
+
+# The test is C++ because the test runner discovers C++; what it exercises is
+# C, and the C++ runtime is the host's, as in the port's own examples/threads-cxx.
+[build]
+cxx_runtime = "host-coupled"
+
+[indices]
+mcpplibs = { path = "../../.." }
diff --git a/tests/examples/openkal-musl/tests/reports.cpp b/tests/examples/openkal-musl/tests/reports.cpp
new file mode 100644
index 00000000..d953b0ea
--- /dev/null
+++ b/tests/examples/openkal-musl/tests/reports.cpp
@@ -0,0 +1,50 @@
+/* The reporters' programs, above openkal-musl. Elsewhere this compiles to a
+ * main() that reports nothing, because the member names the port for Linux
+ * alone. */
+#ifndef HAVE_OPENKAL_MUSL
+int main(void) { return 0; }
+#else
+#define _GNU_SOURCE 1
+#include <dirent.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <pthread.h>
+#include <stdio.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+static int failures = 0;
+
+static void check(int ok, const char* what) { printf("%s %s\n", ok ? "  ok  " : "  FAIL", what); if (!ok) failures++; }
+
+static int open_descriptors(void) {
+    DIR* d = opendir("/proc/self/fd"); if (!d) return -1;
+    int n = 0; while (readdir(d)) n++; closedir(d); return n;
+}
+
+static long recurse(long n) { volatile char pad[1000]; pad[0] = 1; return n ? recurse(n - 1) + pad[0] : 0; }
+static void* body(void* arg) { *(long*)arg = recurse(*(long*)arg); return nullptr; }
+
+int main(void) {
+    char name[64];
+    mkdir("okm.d", 0755);
+    for (int i = 0; i < 300; i++) { snprintf(name, sizeof name, "okm.d/e%03d", i); close(open(name, O_WRONLY | O_CREAT, 0644)); }
+    const int before = open_descriptors();
+    for (int i = 0; i < 64; i++) { DIR* d = opendir("okm.d"); if (d) { readdir(d); closedir(d); } }
+    const int after = open_descriptors();
+    for (int i = 0; i < 300; i++) { snprintf(name, sizeof name, "okm.d/e%03d", i); unlink(name); }
+    rmdir("okm.d");
+    printf("descriptors before=%d after=%d\n", before, after);
+    if (before >= 0) check(before == after, "a directory closed early leaves nothing open");
+
+    pthread_attr_t attr; pthread_t t; long depth = 3900;
+    pthread_attr_init(&attr);
+    pthread_attr_setstacksize(&attr, 4u << 20);
+    check(pthread_create(&t, &attr, body, &depth) == 0 && pthread_join(t, 0) == 0 && depth == 3900,
+          "a thread that asked for 4 MiB recursed 3900 levels of about 1 KiB");
+    static char region[1 << 20];
+    pthread_attr_setstack(&attr, region, sizeof region);
+    check(pthread_create(&t, &attr, body, &depth) == EINVAL, "a stack the caller supplies is refused");
+    return failures != 0;
+}
+#endif
diff --git a/tests/examples/openkal/mcpp.toml b/tests/examples/openkal/mcpp.toml
new file mode 100644
index 00000000..b88bc597
--- /dev/null
+++ b/tests/examples/openkal/mcpp.toml
@@ -0,0 +1,45 @@
+# openkal test project: the specification, the implementation for each runner,
+# and the packages that are consumed only for a target no runner here builds.
+#
+# What it protects. The specification resolves on every runner and its
+# declarations compile there; each implementation resolves, links and answers
+# on its own operating system; and the C-level behaviour of the round that
+# added the newest declarations holds on all three (tests/kal.cpp). A candidate
+# for one of these packages is built only where this manifest names it
+# (tests/autoupdate/ci.py, `member_platforms`): an implementation for another
+# system is not in the host's lock, so asking that runner would prove nothing.
+#
+# The last three entries are named under conditions no runner here builds for
+# --- a musl environment, WebAssembly, a 64-bit RISC-V machine --- so the
+# candidate gate schedules none of them, and their own repositories measure
+# them on their targets.
+[package]
+name    = "openkal-tests"
+version = "0.1.0"
+
+[dependencies.mcpplibs]
+openkal = "0.16.0"
+
+[target.'cfg(os = "linux")'.dependencies.mcpplibs]
+openkal-linux = "0.17.0"
+
+[target.'cfg(os = "macos")'.dependencies.mcpplibs]
+openkal-macos = "0.14.0"
+
+[target.'cfg(windows)'.dependencies.mcpplibs]
+openkal-windows = "0.12.0"
+
+[target.'cfg(all(os = "linux", env = "musl"))'.dependencies.mcpplibs]
+openkal-llvm-runtime = "0.15.5"
+
+[target.'cfg(arch = "wasm32")'.dependencies.mcpplibs]
+openkal-emscripten = "0.5.0"
+
+[target.'cfg(arch = "riscv64")'.dependencies.mcpplibs]
+openkal-opensbi = "0.8.3"
+
+# This member names mcpplibs packages, which the workspace root's single
+# redirect does not carry, so it states its own (mcpp.toml at the root says why
+# a member that needs another namespace declares its own table).
+[indices]
+mcpplibs = { path = "../../.." }
diff --git a/tests/examples/openkal/tests/kal.cpp b/tests/examples/openkal/tests/kal.cpp
new file mode 100644
index 00000000..048105fd
--- /dev/null
+++ b/tests/examples/openkal/tests/kal.cpp
@@ -0,0 +1,65 @@
+// The C surface of openkal through the implementation for this system.
+//
+// One observation per declaration the newest round added, in the terms a
+// caller relies on: a context started with a least stack size is told at least
+// that size and has the room; a closed directory's enumeration is refused; the
+// input position is not an error to ask for. The terminal is not observed here,
+// because a test run has none; the implementations observe it on a terminal
+// they make.
+#include <openkal/fs.h>
+#include <openkal/stream.h>
+#include <openkal/task.h>
+#include <openkal/version.h>
+
+namespace {
+int failures = 0;
+void check(bool ok, const char* what) {
+    if (ok) return;
+    ++failures;
+    kal_uintptr n = 0; while (what[n]) ++n;
+    kal_stream_write(kal_stderr(), "FAIL: ", 6);
+    kal_stream_write(kal_stderr(), what, n);
+    kal_stream_write(kal_stderr(), "\n", 1);
+}
+
+long recurse(long n);
+long (*volatile g_recurse)(long) = recurse;
+long recurse(long n) { volatile char pad[1000]; pad[0] = static_cast<char>(n); return n ? g_recurse(n - 1) + pad[0] : 0; }
+
+struct probe { kal_uintptr told; volatile int done; };
+void room(void* p) {
+    auto* q = static_cast<probe*>(p);
+    void* base = nullptr; kal_uintptr size = 0;
+    if (kal_task_stack(&base, &size) == kal_ok) q->told = size;
+    g_recurse(3 * 1024);
+    q->done = 1;
+}
+}
+
+int main() {
+    check(KAL_VERSION_MINOR >= 16u || KAL_VERSION_MAJOR > 0u, "the declarations are openkal 0.16 or later");
+    check(kal_version() >= KAL_VERSION, "the implementation is at least as new as the declarations");
+
+    probe q{0, 0};
+    kal_task t{};
+    check(kal_task_start_sized(room, &q, 4u << 20, &t) == kal_ok, "a context with a least stack size starts");
+    kal_task_join(t);
+    check(q.told >= (4u << 20), "it is told at least the size asked for");
+    check(q.done == 1, "it has the room");
+
+    kal_dir root{};
+    if (kal_fs_preopen_count() > 0 && kal_fs_preopen(0, &root, nullptr, 0, nullptr) == kal_ok) {
+        kal_fs_mkdir(root, "okt.d", 5);
+        kal_dir d{}; kal_uintptr it = 0;
+        if (kal_fs_open_dir(root, "okt.d", 5, &d) == kal_ok && kal_fs_list_begin(d, &it) == kal_ok) {
+            kal_fs_close_dir(d);
+            char name[64]; kal_uintptr len = 0; int kind = 0;
+            check(kal_fs_list_next(d, &it, name, sizeof name, &len, &kind) == kal_err_invalid,
+                  "an enumeration of a closed directory is refused");
+        }
+        kal_fs_remove(root, "okt.d", 5);
+    }
+
+    if (failures == 0) kal_stream_write(kal_stdout(), "openkal: held\n", 14);
+    return failures == 0 ? 0 : 1;
+}