diff --git a/.github/dependabot.yml b/.github/dependabot.yml
new file mode 100644
index 00000000..0647a0e2
--- /dev/null
+++ b/.github/dependabot.yml
@@ -0,0 +1,80 @@
+# Dependabot — auto-bump pinned dependencies.
+#
+# Why this exists:
+#
+# All `uses:` references in .github/workflows/*.yml are pinned to commit
+# SHAs (with `# v<N>` comments for human readability) instead of mutable
+# tags like `@v4`. Tag pinning is a known supply-chain risk: a maintainer
+# (or compromised maintainer account) can repoint `@v4` to malicious code
+# and our pipelines silently pull it. SHA pinning closes that risk.
+#
+# But SHA pinning has a maintenance cost: each upstream legitimate fix
+# requires manually finding + bumping the SHA. Dependabot for Actions
+# closes that gap by opening PRs to bump pinned SHAs whenever upstream
+# tags a new version. Reviewer evaluates the bump like any other
+# dependency PR.
+#
+# Combined: SHA pinning gives us security, Dependabot keeps us current.
+
+version: 2
+updates:
+  # GitHub Actions — every workflow file under .github/workflows/.
+  # Weekly cadence is enough for a CI surface this size; the supply-
+  # chain attack window is "minutes between repoint and pull," and
+  # weekly auto-bumps don't help with zero-days regardless. The point
+  # is to pull in non-zero-day fixes without operator effort, not to
+  # be real-time.
+  - package-ecosystem: github-actions
+    directory: "/"
+    schedule:
+      interval: weekly
+    open-pull-requests-limit: 5
+    labels:
+      - dependencies
+      - github-actions
+    commit-message:
+      prefix: chore(deps)
+      include: scope
+
+  # Go module — workspace-server. Bumps go.mod deps via PR weekly.
+  - package-ecosystem: gomod
+    directory: "/workspace-server"
+    schedule:
+      interval: weekly
+    open-pull-requests-limit: 5
+    labels:
+      - dependencies
+      - go
+    commit-message:
+      prefix: chore(deps)
+      include: scope
+
+  # npm — canvas (Next.js bundle). Largest dep tree in this repo;
+  # weekly cadence keeps the security surface fresh without flooding
+  # the queue. open-pull-requests-limit: 10 because npm churns more
+  # than the others.
+  - package-ecosystem: npm
+    directory: "/canvas"
+    schedule:
+      interval: weekly
+    open-pull-requests-limit: 10
+    labels:
+      - dependencies
+      - npm
+    commit-message:
+      prefix: chore(deps)
+      include: scope
+
+  # Python — workspace runtime requirements. Pip/requirements.txt-
+  # backed rather than pyproject.toml; Dependabot supports both.
+  - package-ecosystem: pip
+    directory: "/workspace"
+    schedule:
+      interval: weekly
+    open-pull-requests-limit: 5
+    labels:
+      - dependencies
+      - python
+    commit-message:
+      prefix: chore(deps)
+      include: scope
diff --git a/.github/workflows/auto-promote-on-e2e.yml b/.github/workflows/auto-promote-on-e2e.yml
index 21f901e9..ef10c80f 100644
--- a/.github/workflows/auto-promote-on-e2e.yml
+++ b/.github/workflows/auto-promote-on-e2e.yml
@@ -65,7 +65,7 @@ jobs:
           echo "short=${FULL:0:7}" >> "$GITHUB_OUTPUT"
           echo "full=${FULL}" >> "$GITHUB_OUTPUT"
 
-      - uses: imjasonh/setup-crane@v0.4
+      - uses: imjasonh/setup-crane@31b88efe9de28ae0ffa220711af4b60be9435f6e # v0.4
 
       - name: GHCR login
         run: |
diff --git a/.github/workflows/auto-promote-staging.yml b/.github/workflows/auto-promote-staging.yml
index 118d0c83..53946c95 100644
--- a/.github/workflows/auto-promote-staging.yml
+++ b/.github/workflows/auto-promote-staging.yml
@@ -152,7 +152,7 @@ jobs:
 
       - name: Checkout main
         if: ${{ vars.AUTO_PROMOTE_ENABLED == 'true' || github.event.inputs.force == 'true' }}
-        uses: actions/checkout@v4
+        uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
         with:
           ref: main
           fetch-depth: 0
diff --git a/.github/workflows/auto-sync-main-to-staging.yml b/.github/workflows/auto-sync-main-to-staging.yml
index 278c3428..b119712e 100644
--- a/.github/workflows/auto-sync-main-to-staging.yml
+++ b/.github/workflows/auto-sync-main-to-staging.yml
@@ -63,7 +63,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout staging
-        uses: actions/checkout@v4
+        uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
         with:
           fetch-depth: 0
           ref: staging
diff --git a/.github/workflows/auto-tag-runtime.yml b/.github/workflows/auto-tag-runtime.yml
index 2b9070bc..9c1a0222 100644
--- a/.github/workflows/auto-tag-runtime.yml
+++ b/.github/workflows/auto-tag-runtime.yml
@@ -38,7 +38,7 @@ jobs:
   tag:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
         with:
           fetch-depth: 0    # need full tag history for `git describe` / sort
 
diff --git a/.github/workflows/block-internal-paths.yml b/.github/workflows/block-internal-paths.yml
index da56a090..02f14c64 100644
--- a/.github/workflows/block-internal-paths.yml
+++ b/.github/workflows/block-internal-paths.yml
@@ -26,7 +26,7 @@ jobs:
     name: Block forbidden paths
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
         with:
           fetch-depth: 2  # need previous commit to diff against on push events
 
diff --git a/.github/workflows/canary-staging.yml b/.github/workflows/canary-staging.yml
index 65b304aa..30691a82 100644
--- a/.github/workflows/canary-staging.yml
+++ b/.github/workflows/canary-staging.yml
@@ -66,7 +66,7 @@ jobs:
       E2E_RUN_ID: "canary-${{ github.run_id }}"
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
 
       - name: Verify admin token present
         run: |
@@ -98,7 +98,7 @@ jobs:
       # next deploy window.
       - name: Open issue on failure
         if: failure()
-        uses: actions/github-script@v7
+        uses: actions/github-script@f28e40c7f34bde8b3046d885e986cb6290c5673b # v7
         env:
           # Inject the workflow path explicitly — context.workflow is
           # the *name*, not the file path the actions API needs.
@@ -165,7 +165,7 @@ jobs:
 
       - name: Auto-close canary issue on success
         if: success()
-        uses: actions/github-script@v7
+        uses: actions/github-script@f28e40c7f34bde8b3046d885e986cb6290c5673b # v7
         with:
           script: |
             const title = '🔴 Canary failing: staging SaaS smoke';
diff --git a/.github/workflows/canary-verify.yml b/.github/workflows/canary-verify.yml
index 6e560969..c81ae8f3 100644
--- a/.github/workflows/canary-verify.yml
+++ b/.github/workflows/canary-verify.yml
@@ -40,7 +40,7 @@ jobs:
       smoke_ran: ${{ steps.smoke.outputs.ran }}
     steps:
       - name: Checkout
-        uses: actions/checkout@v4
+        uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
 
       - name: Compute sha
         id: compute
@@ -143,7 +143,7 @@ jobs:
     if: ${{ needs.canary-smoke.result == 'success' && needs.canary-smoke.outputs.smoke_ran == 'true' }}
     runs-on: ubuntu-latest
     steps:
-      - uses: imjasonh/setup-crane@v0.4
+      - uses: imjasonh/setup-crane@31b88efe9de28ae0ffa220711af4b60be9435f6e # v0.4
 
       - name: GHCR login
         run: |
diff --git a/.github/workflows/check-merge-group-trigger.yml b/.github/workflows/check-merge-group-trigger.yml
index 77f4c7b3..4345e8b6 100644
--- a/.github/workflows/check-merge-group-trigger.yml
+++ b/.github/workflows/check-merge-group-trigger.yml
@@ -36,7 +36,7 @@ jobs:
     permissions:
       contents: read
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
       - name: Verify merge_group trigger on required-check workflows
         env:
           GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index a9902658..d83f4a0c 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -32,7 +32,7 @@ jobs:
       python: ${{ steps.check.outputs.python }}
       scripts: ${{ steps.check.outputs.scripts }}
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
         with:
           fetch-depth: 0
       - id: check
@@ -72,8 +72,8 @@ jobs:
       run:
         working-directory: workspace-server
     steps:
-      - uses: actions/checkout@v4
-      - uses: actions/setup-go@v5
+      - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
+      - uses: actions/setup-go@40f1582b2485089dde7abd97c1529aa768e1baff # v5
         with:
           go-version: 'stable'
       - run: go mod download
@@ -187,8 +187,8 @@ jobs:
       run:
         working-directory: canvas
     steps:
-      - uses: actions/checkout@v4
-      - uses: actions/setup-node@v4
+      - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
+      - uses: actions/setup-node@49933ea5288caeca8642d1e84afbd3f7d6820020 # v4
         with:
           node-version: '22'
       - run: rm -f package-lock.json && npm install
@@ -210,7 +210,7 @@ jobs:
     if: needs.changes.outputs.scripts == 'true'
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
       - name: Run shellcheck on tests/e2e/*.sh and infra/scripts/*.sh
         # shellcheck is pre-installed on ubuntu-latest runners (via apt).
         # infra/scripts/ is included because setup.sh + nuke.sh gate the
@@ -276,8 +276,8 @@ jobs:
       run:
         working-directory: workspace
     steps:
-      - uses: actions/checkout@v4
-      - uses: actions/setup-python@v5
+      - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
+      - uses: actions/setup-python@a26af69be951a213d495a4c3e4e4022e16d87065 # v5
         with:
           python-version: '3.11'
           cache: pip
diff --git a/.github/workflows/codeql.yml b/.github/workflows/codeql.yml
index 22d095b4..c18b41e9 100644
--- a/.github/workflows/codeql.yml
+++ b/.github/workflows/codeql.yml
@@ -53,14 +53,14 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout@v4
+        uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
 
       - name: Checkout sibling plugin repo
         # Same reasoning as publish-workspace-server-image.yml — the Go
         # module's replace directive needs the plugin source so
         # CodeQL's "go build" phase can resolve.
         if: matrix.language == 'go'
-        uses: actions/checkout@v4
+        uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
         with:
           repository: Molecule-AI/molecule-ai-plugin-github-app-auth
           path: molecule-ai-plugin-github-app-auth
@@ -69,7 +69,7 @@ jobs:
       # jq is pre-installed on ubuntu-latest — no setup step needed.
 
       - name: Initialize CodeQL
-        uses: github/codeql-action/init@v3
+        uses: github/codeql-action/init@ce64ddcb0d8d890d2df4a9d1c04ff297367dea2a # v3
         with:
           languages: ${{ matrix.language }}
           # security-extended widens past the default to include the
@@ -77,11 +77,11 @@ jobs:
           queries: security-extended
 
       - name: Autobuild
-        uses: github/codeql-action/autobuild@v3
+        uses: github/codeql-action/autobuild@ce64ddcb0d8d890d2df4a9d1c04ff297367dea2a # v3
 
       - name: Perform CodeQL Analysis
         id: analyze
-        uses: github/codeql-action/analyze@v3
+        uses: github/codeql-action/analyze@ce64ddcb0d8d890d2df4a9d1c04ff297367dea2a # v3
         with:
           category: "/language:${{ matrix.language }}"
           # upload: never — GHAS isn't enabled on this repo, so the
@@ -121,7 +121,7 @@ jobs:
         # 14-day retention — longer than default 3, short enough not
         # to bloat quota.
         if: always()
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4
         with:
           name: codeql-sarif-${{ matrix.language }}
           path: sarif-results/${{ matrix.language }}/
diff --git a/.github/workflows/e2e-api.yml b/.github/workflows/e2e-api.yml
index d7d6ea09..cb7b4607 100644
--- a/.github/workflows/e2e-api.yml
+++ b/.github/workflows/e2e-api.yml
@@ -36,8 +36,8 @@ jobs:
     outputs:
       api: ${{ steps.decide.outputs.api }}
     steps:
-      - uses: actions/checkout@v4
-      - uses: dorny/paths-filter@v3
+      - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
+      - uses: dorny/paths-filter@d1c1ffe0248fe513906c8e24db8ea791d46f8590 # v3
         id: filter
         with:
           filters: |
@@ -78,8 +78,8 @@ jobs:
       PG_CONTAINER: molecule-ci-postgres
       REDIS_CONTAINER: molecule-ci-redis
     steps:
-      - uses: actions/checkout@v4
-      - uses: actions/setup-go@v5
+      - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
+      - uses: actions/setup-go@40f1582b2485089dde7abd97c1529aa768e1baff # v5
         with:
           go-version: 'stable'
           cache: true
diff --git a/.github/workflows/e2e-staging-canvas.yml b/.github/workflows/e2e-staging-canvas.yml
index 310e16f3..41e2448c 100644
--- a/.github/workflows/e2e-staging-canvas.yml
+++ b/.github/workflows/e2e-staging-canvas.yml
@@ -46,8 +46,8 @@ jobs:
     outputs:
       canvas: ${{ steps.decide.outputs.canvas }}
     steps:
-      - uses: actions/checkout@v4
-      - uses: dorny/paths-filter@v3
+      - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
+      - uses: dorny/paths-filter@d1c1ffe0248fe513906c8e24db8ea791d46f8590 # v3
         id: filter
         with:
           filters: |
@@ -90,7 +90,7 @@ jobs:
         working-directory: canvas
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
 
       - name: Verify admin token present
         run: |
@@ -100,7 +100,7 @@ jobs:
           fi
 
       - name: Set up Node
-        uses: actions/setup-node@v4
+        uses: actions/setup-node@49933ea5288caeca8642d1e84afbd3f7d6820020 # v4
         with:
           node-version: '20'
           cache: 'npm'
@@ -117,7 +117,7 @@ jobs:
 
       - name: Upload Playwright report on failure
         if: failure()
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4
         with:
           name: playwright-report-staging
           path: canvas/playwright-report-staging/
@@ -125,7 +125,7 @@ jobs:
 
       - name: Upload screenshots on failure
         if: failure()
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4
         with:
           name: playwright-screenshots
           path: canvas/test-results/
diff --git a/.github/workflows/e2e-staging-saas.yml b/.github/workflows/e2e-staging-saas.yml
index 39ee38a2..1c6d04bf 100644
--- a/.github/workflows/e2e-staging-saas.yml
+++ b/.github/workflows/e2e-staging-saas.yml
@@ -92,7 +92,7 @@ jobs:
       E2E_KEEP_ORG: ${{ github.event.inputs.keep_org && '1' || '0' }}
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
 
       - name: Verify admin token present
         run: |
diff --git a/.github/workflows/e2e-staging-sanity.yml b/.github/workflows/e2e-staging-sanity.yml
index 6eacac36..e645a58f 100644
--- a/.github/workflows/e2e-staging-sanity.yml
+++ b/.github/workflows/e2e-staging-sanity.yml
@@ -50,7 +50,7 @@ jobs:
       E2E_INTENTIONAL_FAILURE: "1"
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
 
       - name: Verify admin token present
         run: |
@@ -89,7 +89,7 @@ jobs:
 
       - name: Open issue if safety net is broken
         if: failure()
-        uses: actions/github-script@v7
+        uses: actions/github-script@f28e40c7f34bde8b3046d885e986cb6290c5673b # v7
         with:
           script: |
             const title = "🚨 E2E teardown safety net broken";
diff --git a/.github/workflows/promote-latest.yml b/.github/workflows/promote-latest.yml
index 896f216c..2be7e023 100644
--- a/.github/workflows/promote-latest.yml
+++ b/.github/workflows/promote-latest.yml
@@ -34,7 +34,7 @@ jobs:
   promote:
     runs-on: ubuntu-latest
     steps:
-      - uses: imjasonh/setup-crane@v0.4
+      - uses: imjasonh/setup-crane@31b88efe9de28ae0ffa220711af4b60be9435f6e # v0.4
 
       - name: GHCR login
         run: |
diff --git a/.github/workflows/publish-canvas-image.yml b/.github/workflows/publish-canvas-image.yml
index e957169d..b7a34aeb 100644
--- a/.github/workflows/publish-canvas-image.yml
+++ b/.github/workflows/publish-canvas-image.yml
@@ -42,17 +42,17 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v4
+        uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
 
       - name: Log in to GHCR
-        uses: docker/login-action@v3
+        uses: docker/login-action@c94ce9fb468520275223c153574b00df6fe4bcc9 # v3
         with:
           registry: ghcr.io
           username: ${{ github.actor }}
           password: ${{ secrets.GITHUB_TOKEN }}
 
       - name: Set up Docker Buildx
-        uses: docker/setup-buildx-action@v3
+        uses: docker/setup-buildx-action@8d2750c68a42422c14e847fe6c8ac0403b4cbd6f # v3
 
       - name: Compute tags
         id: tags
@@ -85,7 +85,7 @@ jobs:
           echo "ws_url=${WS_URL}" >> "$GITHUB_OUTPUT"
 
       - name: Build & push canvas image to GHCR
-        uses: docker/build-push-action@v6
+        uses: docker/build-push-action@10e90e3645eae34f1e60eeb005ba3a3d33f178e8 # v6
         with:
           context: ./canvas
           file: ./canvas/Dockerfile
diff --git a/.github/workflows/publish-runtime.yml b/.github/workflows/publish-runtime.yml
index 516f8f98..83f87df3 100644
--- a/.github/workflows/publish-runtime.yml
+++ b/.github/workflows/publish-runtime.yml
@@ -81,9 +81,9 @@ jobs:
       version: ${{ steps.version.outputs.version }}
       wheel_sha256: ${{ steps.wheel_hash.outputs.wheel_sha256 }}
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
 
-      - uses: actions/setup-python@v5
+      - uses: actions/setup-python@a26af69be951a213d495a4c3e4e4022e16d87065 # v5
         with:
           python-version: "3.11"
           cache: pip
diff --git a/.github/workflows/publish-workspace-server-image.yml b/.github/workflows/publish-workspace-server-image.yml
index c7f3127f..d47a887d 100644
--- a/.github/workflows/publish-workspace-server-image.yml
+++ b/.github/workflows/publish-workspace-server-image.yml
@@ -27,7 +27,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v4
+        uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
 
       - name: Checkout sibling plugin repo
         # workspace-server/Dockerfile expects
@@ -42,21 +42,21 @@ jobs:
         # The PAT needs Contents:Read on Molecule-AI/molecule-ai-plugin-
         # github-app-auth. Falls back to the default token for the (rare)
         # case where an operator made the plugin repo public.
-        uses: actions/checkout@v4
+        uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
         with:
           repository: Molecule-AI/molecule-ai-plugin-github-app-auth
           path: molecule-ai-plugin-github-app-auth
           token: ${{ secrets.PLUGIN_REPO_PAT || secrets.GITHUB_TOKEN }}
 
       - name: Log in to GHCR
-        uses: docker/login-action@v3
+        uses: docker/login-action@c94ce9fb468520275223c153574b00df6fe4bcc9 # v3
         with:
           registry: ghcr.io
           username: ${{ github.actor }}
           password: ${{ secrets.GITHUB_TOKEN }}
 
       - name: Set up Docker Buildx
-        uses: docker/setup-buildx-action@v3
+        uses: docker/setup-buildx-action@8d2750c68a42422c14e847fe6c8ac0403b4cbd6f # v3
 
       - name: Compute tags
         id: tags
@@ -87,7 +87,7 @@ jobs:
       # applyRuntimeModelEnv and caused every E2E to route hermes+openai
       # through openrouter → 401). See issue filed with this PR.
       - name: Build & push platform image to GHCR (staging-<sha> + staging-latest)
-        uses: docker/build-push-action@v6
+        uses: docker/build-push-action@10e90e3645eae34f1e60eeb005ba3a3d33f178e8 # v6
         with:
           context: .
           file: ./workspace-server/Dockerfile
@@ -104,7 +104,7 @@ jobs:
             org.opencontainers.image.description=Molecule AI platform (Go API server) — pending canary verify
 
       - name: Build & push tenant image to GHCR (staging-<sha> + staging-latest)
-        uses: docker/build-push-action@v6
+        uses: docker/build-push-action@10e90e3645eae34f1e60eeb005ba3a3d33f178e8 # v6
         with:
           context: .
           file: ./workspace-server/Dockerfile.tenant
diff --git a/.github/workflows/runtime-pin-compat.yml b/.github/workflows/runtime-pin-compat.yml
index 2672f355..919ddd70 100644
--- a/.github/workflows/runtime-pin-compat.yml
+++ b/.github/workflows/runtime-pin-compat.yml
@@ -60,8 +60,8 @@ jobs:
     name: PyPI-latest install + import smoke
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
-      - uses: actions/setup-python@v5
+      - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
+      - uses: actions/setup-python@a26af69be951a213d495a4c3e4e4022e16d87065 # v5
         with:
           python-version: '3.11'
           cache: pip
diff --git a/.github/workflows/runtime-prbuild-compat.yml b/.github/workflows/runtime-prbuild-compat.yml
index 41f8332a..0c8a14c4 100644
--- a/.github/workflows/runtime-prbuild-compat.yml
+++ b/.github/workflows/runtime-prbuild-compat.yml
@@ -61,8 +61,8 @@ jobs:
     name: PR-built wheel + import smoke
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
-      - uses: actions/setup-python@v5
+      - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
+      - uses: actions/setup-python@a26af69be951a213d495a4c3e4e4022e16d87065 # v5
         with:
           python-version: '3.11'
           cache: pip
diff --git a/.github/workflows/secret-scan.yml b/.github/workflows/secret-scan.yml
index cebf89e9..b5ffd550 100644
--- a/.github/workflows/secret-scan.yml
+++ b/.github/workflows/secret-scan.yml
@@ -40,7 +40,7 @@ jobs:
     name: Scan diff for credential-shaped strings
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
         with:
           fetch-depth: 2  # need previous commit to diff against on push events
 
diff --git a/.github/workflows/sweep-cf-orphans.yml b/.github/workflows/sweep-cf-orphans.yml
index 7fb35328..c1033b26 100644
--- a/.github/workflows/sweep-cf-orphans.yml
+++ b/.github/workflows/sweep-cf-orphans.yml
@@ -78,7 +78,7 @@ jobs:
       MAX_DELETE_PCT: ${{ github.event.inputs.max_delete_pct || '50' }}
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
 
       - name: Verify required secrets present
         id: verify
diff --git a/.github/workflows/test-ops-scripts.yml b/.github/workflows/test-ops-scripts.yml
index 9a3a5fa3..6a3bee85 100644
--- a/.github/workflows/test-ops-scripts.yml
+++ b/.github/workflows/test-ops-scripts.yml
@@ -27,8 +27,8 @@ jobs:
     name: Ops scripts (unittest)
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
-      - uses: actions/setup-python@v5
+      - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
+      - uses: actions/setup-python@a26af69be951a213d495a4c3e4e4022e16d87065 # v5
         with:
           python-version: '3.11'
       - name: Run unittest