diff --git a/.github/workflows/validate-packages.yml b/.github/workflows/validate-packages.yml
index b5112b6..2665d3d 100644
--- a/.github/workflows/validate-packages.yml
+++ b/.github/workflows/validate-packages.yml
@@ -137,3 +137,31 @@ jobs:
             exit 1
           fi
           echo "directory.json is in sync with the package manifests"
+
+      # The security overrides only work if pnpm actually reads them. pnpm 11
+      # ignores a `pnpm` field in package.json outright and SILENTLY, so an
+      # override block that drifts back there would leave the repo looking
+      # patched while shipping vulnerable transitive deps. Fail loudly instead.
+      - name: Check pnpm overrides are where pnpm reads them
+        shell: bash
+        run: |
+          set -euo pipefail
+          if node -e "process.exit(require('./package.json').pnpm ? 0 : 1)"; then
+            echo "::error::package.json has a 'pnpm' field. pnpm 11 ignores it silently — move these settings to pnpm-workspace.yaml."
+            exit 1
+          fi
+          if ! grep -q '^overrides:' pnpm-workspace.yaml; then
+            echo "::error::pnpm-workspace.yaml has no overrides block — the transitive security patches are missing."
+            exit 1
+          fi
+          # Every override must actually appear in the resolved lockfile.
+          missing=0
+          while read -r pkg; do
+            [ -z "$pkg" ] && continue
+            if ! grep -qE "^  '?${pkg}'?:" pnpm-lock.yaml; then
+              echo "::error::override '${pkg}' is not recorded in pnpm-lock.yaml — it is not taking effect."
+              missing=1
+            fi
+          done < <(sed -n '/^overrides:/,$p' pnpm-workspace.yaml | tail -n +2 | sed -n 's/^  "\{0,1\}\([^":]*\)"\{0,1\}:.*/\1/p')
+          [ "$missing" -eq 0 ] || exit 1
+          echo "pnpm overrides live in pnpm-workspace.yaml and are all present in the lockfile"
diff --git a/package.json b/package.json
index 1d87cf6..d14128d 100644
--- a/package.json
+++ b/package.json
@@ -55,20 +55,5 @@
     "node": ">=24",
     "pnpm": ">=10"
   },
-  "packageManager": "pnpm@10.33.0",
-  "//pnpm-overrides": "Security patches for transitive dependencies. Each range is pinned to the SAME major as the version Astro's tree already resolves \u2014 a bare '>=' pulls in the next major (js-yaml 5, undici 8, fast-uri 4, svgo 4) and breaks the build. esbuild is deliberately NOT overridden: the only open advisory (GHSA, low) is an arbitrary file read in esbuild's dev server on Windows, which this repo never runs \u2014 it builds a static site in CI \u2014 and forcing >=0.28.1 breaks @astrojs/vue. Revisit all of these when Astro is upgraded; several may become unnecessary.",
-  "pnpm": {
-    "overrides": {
-      "@babel/core": "^7.29.6",
-      "fast-uri": "~3.1.4",
-      "js-yaml": "^4.3.0",
-      "postcss": "^8.5.18",
-      "sharp": "^0.35.3",
-      "svgo": "^3.3.4",
-      "tar": "^7.5.18",
-      "undici": "^7.28.0",
-      "vite": "^6.4.3",
-      "yaml": "^2.8.3"
-    }
-  }
+  "packageManager": "pnpm@10.33.0"
 }
diff --git a/pnpm-workspace.yaml b/pnpm-workspace.yaml
new file mode 100644
index 0000000..920b9ae
--- /dev/null
+++ b/pnpm-workspace.yaml
@@ -0,0 +1,28 @@
+# pnpm reads its settings from THIS file, not from a `pnpm` field in
+# package.json. Since pnpm 11 the package.json field is ignored outright — and
+# silently, with no warning — so overrides defined there become inert while the
+# repo still looks patched. These are security patches for transitive
+# dependencies, so they live here where both pnpm 10 and 11 honour them.
+#
+# Each range is pinned to the SAME major the tree already resolves: a bare
+# ">=" pulls the next major (js-yaml 5, undici 8, fast-uri 4, svgo 4) and
+# breaks the build. esbuild is deliberately absent — its only advisory is a low
+# severity dev-server file read on Windows, which this repo never runs, and
+# forcing >=0.28.1 breaks @astrojs/vue.
+#
+# Revisit when Astro is upgraded; several may become unnecessary.
+
+packages:
+  - .
+
+overrides:
+  "@babel/core": "^7.29.6"
+  fast-uri: "~3.1.4"
+  js-yaml: "^4.3.0"
+  postcss: "^8.5.18"
+  sharp: "^0.35.3"
+  svgo: "^3.3.4"
+  tar: "^7.5.18"
+  undici: "^7.28.0"
+  vite: "^6.4.3"
+  yaml: "^2.8.3"