diff --git a/.github/dependabot.yml b/.github/dependabot.yml
index 473f420a..5b15db40 100644
--- a/.github/dependabot.yml
+++ b/.github/dependabot.yml
@@ -24,3 +24,11 @@ updates:
         update-types:
           - minor
           - patch
+
+  - package-ecosystem: github-actions
+    directory: /
+    schedule:
+      interval: weekly
+    cooldown:
+      # gives a hijacked action release time to be caught before it is proposed
+      default-days: 7
diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index 8c26b954..8a385ed2 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -13,9 +13,9 @@ jobs:
   check:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v7
+      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
 
-      - uses: pnpm/action-setup@v6
+      - uses: pnpm/action-setup@ea17c68df8912ef543352723c149a84f56e3d413 # v6.1.0
 
       - run: pnpm i
 
@@ -28,9 +28,9 @@ jobs:
         node-version: [26, 24, 22, 20]
       fail-fast: false
     steps:
-      - uses: actions/checkout@v7
+      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
 
-      - uses: pnpm/action-setup@v6
+      - uses: pnpm/action-setup@ea17c68df8912ef543352723c149a84f56e3d413 # v6.1.0
 
       - run: pnpm runtime set node ${{ matrix.node-version }}
 
@@ -40,7 +40,7 @@ jobs:
 
       - run: pnpm run test:coverage
 
-      - uses: codecov/codecov-action@v7
+      - uses: codecov/codecov-action@303a32d7a59b442fa8d48b6a1cc6825c09c847a5 # v7.1.1
         # TODO: use v26, there're tests skipped on v26
         if: matrix.node-version == 24
         with:
@@ -49,9 +49,9 @@ jobs:
   publish_preview:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v7
+      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
 
-      - uses: pnpm/action-setup@v6
+      - uses: pnpm/action-setup@ea17c68df8912ef543352723c149a84f56e3d413 # v6.1.0
 
       - run: pnpm i
 
diff --git a/.github/workflows/codspeed.yaml b/.github/workflows/codspeed.yaml
index de63dc42..42a4dabe 100644
--- a/.github/workflows/codspeed.yaml
+++ b/.github/workflows/codspeed.yaml
@@ -17,13 +17,13 @@ jobs:
   benchmarks:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v7
+      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
 
-      - uses: pnpm/action-setup@v6
+      - uses: pnpm/action-setup@ea17c68df8912ef543352723c149a84f56e3d413 # v6.1.0
 
       - run: pnpm i
 
-      - uses: CodSpeedHQ/action@v4
+      - uses: CodSpeedHQ/action@f22792bfac16f3e14eb9fbea76f4a48e9cc22b93 # v4.19.1
         with:
           mode: simulation
           run: pnpm run bench
diff --git a/.github/workflows/pullfrog.yml b/.github/workflows/pullfrog.yml
index c84c88c8..3b196fe8 100644
--- a/.github/workflows/pullfrog.yml
+++ b/.github/workflows/pullfrog.yml
@@ -22,11 +22,11 @@ jobs:
       contents: read
     steps:
       - name: Checkout code
-        uses: actions/checkout@v6
+        uses: actions/checkout@d23441a48e516b6c34aea4fa41551a30e30af803 # v6.1.0
         with:
           fetch-depth: 1
       - name: Run agent
-        uses: pullfrog/pullfrog@v0
+        uses: pullfrog/pullfrog@ad4283a862b8377cb525a0f5bf30f17c023b18ea # v0.1.98
         with:
           prompt: ${{ inputs.prompt }}
         env:
diff --git a/.github/workflows/release.yaml b/.github/workflows/release.yaml
index b79e9b76..09e24c25 100644
--- a/.github/workflows/release.yaml
+++ b/.github/workflows/release.yaml
@@ -33,7 +33,9 @@ concurrency:
 
 jobs:
   release:
+    if: github.ref == 'refs/heads/main'
     runs-on: ubuntu-latest
+    environment: npm-release
     permissions:
       contents: write
       id-token: write
@@ -62,11 +64,11 @@ jobs:
           fi
           echo "tag=$TAG" >> "$GITHUB_OUTPUT"
 
-      - uses: actions/checkout@v7
+      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
         with:
           fetch-depth: 0
 
-      - uses: pnpm/action-setup@v6
+      - uses: pnpm/action-setup@ea17c68df8912ef543352723c149a84f56e3d413 # v6.1.0
 
       - run: pnpm i
 
diff --git a/.github/workflows/sponsors-sync.yaml b/.github/workflows/sponsors-sync.yaml
index 68a2225c..56ac241e 100644
--- a/.github/workflows/sponsors-sync.yaml
+++ b/.github/workflows/sponsors-sync.yaml
@@ -11,18 +11,20 @@ jobs:
     permissions:
       contents: write
     steps:
-      - uses: actions/checkout@v7
+      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
 
-      - uses: pnpm/action-setup@v6
+      - uses: pnpm/action-setup@ea17c68df8912ef543352723c149a84f56e3d413 # v6.1.0
 
       - run: pnpm i
 
       - run: pnpm run sponsors:sync
 
-      - uses: EndBug/add-and-commit@v10
-        with:
-          author_name: GitHub Actions
-          author_email: 41898282+github-actions[bot]@users.noreply.github.com
-          message: 'chore: sync sponsors'
-        env:
-          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+      - name: Commit and push changes
+        run: |
+          git add .
+          if git diff --cached --quiet; then
+            echo "No changes to commit"
+            exit 0
+          fi
+          git -c user.name="GitHub Actions" -c user.email="41898282+github-actions[bot]@users.noreply.github.com" commit -m "chore: sync sponsors"
+          git push origin HEAD
diff --git a/tests/github-workflows.test.ts b/tests/github-workflows.test.ts
new file mode 100644
index 00000000..b5d59318
--- /dev/null
+++ b/tests/github-workflows.test.ts
@@ -0,0 +1,60 @@
+import { readdirSync, readFileSync } from 'node:fs'
+import { join } from 'node:path'
+import { fileURLToPath } from 'node:url'
+
+const githubDir = fileURLToPath(new URL('../.github/', import.meta.url))
+const workflowsDir = join(githubDir, 'workflows')
+
+const workflows = readdirSync(workflowsDir)
+  .filter((name) => /\.ya?ml$/.test(name))
+  .map((name) => ({ name, content: readFileSync(join(workflowsDir, name), 'utf8') }))
+
+/**
+ * Collects every `uses:` reference across all workflows, with its version comment if any.
+ */
+function collectUses(): { location: string; ref: string; comment: string | undefined }[] {
+  return workflows.flatMap(({ name, content }) =>
+    content.split('\n').flatMap((line, index) => {
+      const match = /^\s*(?:-\s+)?uses:\s*(['"]?)([^\s'"]+)\1(?:\s+#\s*(.*?))?\s*$/.exec(line)
+      return match ? [{ location: `${name}:${index + 1}`, ref: match[2]!, comment: match[3] }] : []
+    }),
+  )
+}
+
+describe('github workflows', () => {
+  it('pins every third-party action to a full commit SHA with a version comment', () => {
+    const uses = collectUses().filter(({ ref }) => !ref.startsWith('./'))
+    expect(uses.length).toBeGreaterThan(0)
+
+    const unpinned = uses
+      .filter(
+        ({ ref, comment }) =>
+          !/@[0-9a-f]{40}$/.test(ref) || !/^v\d+\.\d+\.\d+$/.test(comment ?? ''),
+      )
+      .map(
+        ({ location, ref, comment }) =>
+          `${location}: ${ref}${comment === undefined ? '' : ` # ${comment}`}`,
+      )
+    expect(unpinned).toEqual([])
+  })
+
+  it('keeps action pins updated through dependabot', () => {
+    expect(readFileSync(join(githubDir, 'dependabot.yml'), 'utf8')).toMatch(
+      /^\s*-\s+package-ecosystem:\s*github-actions\s*$/m,
+    )
+  })
+
+  it('gates the release job behind an environment and the main branch', () => {
+    const release = readFileSync(join(workflowsDir, 'release.yaml'), 'utf8')
+    expect(release).toMatch(/^\s+environment:\s*npm-release\s*$/m)
+    expect(release).toMatch(/^\s+if:\s*github\.ref\s*==\s*'refs\/heads\/main'\s*$/m)
+  })
+
+  it('does not hand a write token to EndBug/add-and-commit', () => {
+    expect(
+      workflows
+        .filter(({ content }) => content.includes('EndBug/add-and-commit'))
+        .map(({ name }) => name),
+    ).toEqual([])
+  })
+})