diff --git a/.claude/agent-memory/archgate-developer/project_shim_publishing.md b/.claude/agent-memory/archgate-developer/project_shim_publishing.md
index 49714d34..73af813a 100644
--- a/.claude/agent-memory/archgate-developer/project_shim_publishing.md
+++ b/.claude/agent-memory/archgate-developer/project_shim_publishing.md
@@ -9,8 +9,8 @@ metadata:
 
 **When editing any shim under `shims/` or `publish-shims.yml`:**
 
-- **PyPI** (`shims/pypi/`): `pyproject.toml` declares `readme = "README.md"`, so `shims/pypi/README.md` MUST exist or `python -m build` fails with `OSError: Readme file does not exist`.
-- **RubyGem** (`shims/rubygem/`): `rubygems/release-gem` runs `bundle exec rake release` from its `working-directory`. Requires (1) `working-directory: shims/rubygem` on BOTH `ruby/setup-ruby` (with `bundler-cache: true`) and `rubygems/release-gem`; (2) a `shims/rubygem/Rakefile` with `require "bundler/gem_tasks"` for the `release` task. Do NOT commit `Gemfile.lock` — bundler-cache generates it untracked, keeping `release:guard_clean` happy.
+- **PyPI** (`shims/pypi/`): `pyproject.toml` declares `readme = "README.md"`, so `shims/pypi/README.md` MUST exist or the build fails with `OSError: Readme file does not exist`. The job builds with **`uv build --python 3.12`** (via `astral-sh/setup-uv`, SHA-pinned) — uv provisions its own version-pinned, isolated build env, so there is no `pip install build` line for Scorecard Pinned-Dependencies to flag. Do NOT reintroduce the `pip install build==X --hash=...` form: **`--hash` is NOT a valid `pip install` command-line option** (only valid inside a requirements file), so it fails with `no such option: --hash` — that broke the v0.41.0 release (introduced unverified in #361 since the workflow only runs at release time).
+- **RubyGem** (`shims/rubygem/`): `rubygems/release-gem` runs `bundle exec rake release` from its `working-directory`. Requires (1) `working-directory: shims/rubygem` on BOTH `ruby/setup-ruby` (with `bundler-cache: true`) and `rubygems/release-gem`; (2) a `shims/rubygem/Rakefile` with `require "bundler/gem_tasks"` for the `release` task; (3) **`gem "rake"` declared in `shims/rubygem/Gemfile`** — Ruby 4.0 no longer ships rake as a bundled default gem, so `bundle exec rake` fails with `rake is not currently included in the bundle` (broke the v0.41.0 release when the runner moved to Ruby 4.0.5). Do NOT commit `Gemfile.lock` — bundler-cache generates it untracked, keeping `release:guard_clean` happy.
 - **Maven** (`shims/maven/pom.xml`): use `<waitUntil>validated</waitUntil>` with `<autoPublish>true</autoPublish>`, NOT `<waitUntil>published</waitUntil>` — the latter blocks until Sonatype finishes publishing, which routinely exceeds the job timeout (upload succeeds, then the build hangs on "Waiting until Deployment ... is published").
 
 **Re-runs are not idempotent:** `publish-go-tag` (creates a git tag), `publish-nuget`, and an already-uploaded Maven deploy fail on "already exists" on a second run. After a partial failure, apply the fix to the next version bump or `workflow_dispatch` only the failed ecosystems.
diff --git a/.github/workflows/publish-shims.yml b/.github/workflows/publish-shims.yml
index 7e832565..cd818efd 100644
--- a/.github/workflows/publish-shims.yml
+++ b/.github/workflows/publish-shims.yml
@@ -58,17 +58,14 @@ jobs:
       - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
         with:
           ref: ${{ github.event.release.tag_name || inputs.tag }}
-      - uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6
+      - uses: astral-sh/setup-uv@08807647e7069bb48b6ef5acd8ec9567f424441b # v8.1.0
         with:
           python-version: "3.12"
       - name: Build package
         working-directory: shims/pypi
-        run: |
-          pip install 'build==1.5.0' \
-            --require-hashes \
-            --hash=sha256:13f3eecb844759ab66efec90ca17639bbf14dc06cb2fdf37a9010322d9c50a6f \
-            --hash=sha256:302c22c3ba2a0fd5f3911918651341ebb3896176cbdec15bd421f80b1afc7647
-          python -m build
+        # `uv build` provisions an isolated, version-pinned build environment
+        # itself — no unpinned `pip install build` (Scorecard Pinned-Dependencies).
+        run: uv build
       - name: Publish to PyPI
         uses: pypa/gh-action-pypi-publish@cef221092ed1bacb1cc03d23a2d87d1d172e277b # v1.14.0
         with:
diff --git a/shims/rubygem/Gemfile b/shims/rubygem/Gemfile
index 838eb874..208d60ac 100644
--- a/shims/rubygem/Gemfile
+++ b/shims/rubygem/Gemfile
@@ -4,6 +4,10 @@ source "https://rubygems.org"
 
 gemspec
 
+# rake is required by `bundle exec rake release` (rubygems/release-gem action).
+# Ruby 4.0 no longer ships rake as a bundled default gem, so it must be declared.
+gem "rake", "~> 13.0"
+
 group :test do
   gem "minitest", "~> 6.0"
   gem "minitest-mock", "~> 5.0"