diff --git a/.github/scripts/check-deps-and-qt.sh b/.github/scripts/check-deps-and-qt.sh
index c73eb98..08b9b69 100644
--- a/.github/scripts/check-deps-and-qt.sh
+++ b/.github/scripts/check-deps-and-qt.sh
@@ -141,6 +141,12 @@ vcpkg_workspace() {
     [ "$(find . -path '*/target/*' -path '*deps-vcpkg*' -name '*.stamp' | wc -l)" -ge 2 ] ||
         fail "each member did not declare its own installation"
     echo "ok: two members that share no dependency both installed and linked one prefix"
+    # The two installations may run at once; vcpkg's own lock on the root makes
+    # the second wait only when asked to, and fails it otherwise ("failed to
+    # take lock", measured on GalTranslPP under 0.15.0).
+    [ "$(grep -rl -- '--x-wait-for-lock' --include=build.ninja . | wc -l)" -ge 2 ] ||
+        fail "a member's installation does not wait for the root's lock"
+    echo "ok: each member's installation waits for another one of the same root"
 }
 
 cmake_consumer() {
diff --git a/README.md b/README.md
index 7f041ff..3772b9b 100644
--- a/README.md
+++ b/README.md
@@ -9,7 +9,7 @@ module name the member declares, and configures it there.
 
 ```toml
 [build-dependencies.mcpp]
-plugins = { version = "0.15.0", features = ["rules-spirv"], host-module = true }
+plugins = { version = "0.15.1", features = ["rules-spirv"], host-module = true }
 ```
 
 ```cpp
diff --git a/deps/vcpkg.cppm b/deps/vcpkg.cppm
index a9d3f3e..68bbf5c 100644
--- a/deps/vcpkg.cppm
+++ b/deps/vcpkg.cppm
@@ -274,8 +274,10 @@ inline prefix use(const options& opt = {}) {
         // THE ACTION IS vcpkg ITSELF. Everything an installation needs is an
         // argument: `--vcpkg-root` pairs the tool with the scripts it was
         // released with, whatever `VCPKG_ROOT` the shell has; vcpkg locks the
-        // installation root itself (`<root>/vcpkg/vcpkg-running.lock`), so two
-        // workspace members installing one root wait for each other; its build
+        // installation root itself (`<root>/vcpkg/vcpkg-running.lock`), and
+        // `--x-wait-for-lock` makes a second installation of the same root --
+        // two workspace members, run concurrently -- wait for the first
+        // instead of failing (measured on GalTranslPP under 0.15.0); its build
         // and package trees go to a short directory under vcpkg's per-user
         // directory, because a port's build nests deep and Windows tools still
         // enforce MAX_PATH.
@@ -295,6 +297,7 @@ inline prefix use(const options& opt = {}) {
         a.arg(exeS.c_str()).arg("install")
          .arg(("--vcpkg-root=" + vcpkgRoot).c_str())
          .arg("--disable-metrics")
+         .arg("--x-wait-for-lock")
          .arg("--triplet").arg(triplet.c_str())
          .arg(("--x-manifest-root=" + mcpp::deps::generic(manifestRoot)).c_str())
          .arg(("--x-install-root=" + mcpp::deps::generic(tripletRoot)).c_str())
diff --git a/docs/deps.md b/docs/deps.md
index 4690ffe..9e4596e 100644
--- a/docs/deps.md
+++ b/docs/deps.md
@@ -24,7 +24,7 @@ Module `mcpp.deps.archive`; engine floor: 2026.9.26.2.
 
 ```toml
 [build-dependencies.mcpp]
-plugins = { version = "0.15.0", features = ["deps-vcpkg"], host-module = true }
+plugins = { version = "0.15.1", features = ["deps-vcpkg"], host-module = true }
 ```
 
 ```cpp
@@ -88,8 +88,9 @@ vcpkg's per-user directory (`%LOCALAPPDATA%\vcpkg` on Windows,
 `$XDG_CACHE_HOME/vcpkg` or `~/.cache/vcpkg` elsewhere), beside vcpkg's default
 binary cache, under a short name, because Windows tools still enforce MAX_PATH;
 an existing `VCPKG_DOWNLOADS` is kept. vcpkg locks the installation root itself
-(`<root>/vcpkg/vcpkg-running.lock`), so two workspace members installing one
-root run one after the other. vcpkg fetches its
+(`<root>/vcpkg/vcpkg-running.lock`), and `--x-wait-for-lock` makes two
+workspace members installing one root run one after the other; without it the
+second fails, "failed to take lock" (0.15.1). vcpkg fetches its
 own CMake, Ninja and 7-Zip, and on Windows a portable git; on Linux and macOS
 its documented host prerequisites (git, curl, zip, unzip, tar, a C compiler)
 are the host's. Ports are compiled with vcpkg's default toolchain for the
diff --git a/docs/rules-qt.md b/docs/rules-qt.md
index 2e1e487..f5fc9cb 100644
--- a/docs/rules-qt.md
+++ b/docs/rules-qt.md
@@ -6,7 +6,7 @@
 
 ```toml
 [build-dependencies.mcpp]
-plugins = { version = "0.15.0", features = ["rules-qt"], host-module = true }
+plugins = { version = "0.15.1", features = ["rules-qt"], host-module = true }
 
 # The SDK and its version are the project's declaration.
 [target.'cfg(any(windows, linux, macos))'.xlings.workspace]
diff --git a/mcpp.toml b/mcpp.toml
index ebec8de..cd6e554 100644
--- a/mcpp.toml
+++ b/mcpp.toml
@@ -1,7 +1,7 @@
 [package]
 name        = "plugins"
 namespace   = "mcpp"
-version     = "0.15.0"
+version     = "0.15.1"
 description = "Official mcpp build plugins: rule packages under mcpp.rules.*, build-time utilities under mcpp.tools.*, each member selected by a feature"
 license     = "Apache-2.0"
 authors     = ["mcpp-community"]
diff --git a/src/plugins.cppm b/src/plugins.cppm
index f06f9d6..7e6443a 100644
--- a/src/plugins.cppm
+++ b/src/plugins.cppm
@@ -49,7 +49,7 @@ export namespace mcpp::plugins {
 //
 // One package, one version: the number lives in mcpp.toml, and the CI step
 // `the collection states its own version` compares the two.
-inline constexpr std::string_view version = "0.15.0";
+inline constexpr std::string_view version = "0.15.1";
 
 } // namespace mcpp::plugins
 
diff --git a/tests/vcpkg-workspace/mcpp.toml b/tests/vcpkg-workspace/mcpp.toml
index 13ccc09..0cbaab6 100644
--- a/tests/vcpkg-workspace/mcpp.toml
+++ b/tests/vcpkg-workspace/mcpp.toml
@@ -5,7 +5,8 @@
 # it, and those of no other package do, so each member declares the
 # installation itself. The two actions run the same `vcpkg install` against the
 # root's one manifest into one installation root; vcpkg locks that root itself
-# (`vcpkg/vcpkg-running.lock`), so they run one after the other and the second
+# (`vcpkg/vcpkg-running.lock`) and the member passes `--x-wait-for-lock`, so
+# they run one after the other and the second
 # finds everything installed.
 [workspace]
 members = ["app-a", "app-b"]