diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 5417f44..40e7ec7 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -8,10 +8,10 @@ jobs:
   test:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6.0.3
 
       - name: Install uv
-        uses: astral-sh/setup-uv@v5
+        uses: astral-sh/setup-uv@fac544c07dec837d0ccb6301d7b5580bf5edae39 # v8.2.0
         with:
           python-version: "3.11"
 
diff --git a/.github/workflows/codex-review.yml b/.github/workflows/codex-review.yml
index 20a8f02..16a39ba 100644
--- a/.github/workflows/codex-review.yml
+++ b/.github/workflows/codex-review.yml
@@ -13,7 +13,7 @@ jobs:
   review:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6.0.3
         with:
           fetch-depth: 0
 
diff --git a/.github/workflows/contract-drift.yml b/.github/workflows/contract-drift.yml
index 89308a3..789c792 100644
--- a/.github/workflows/contract-drift.yml
+++ b/.github/workflows/contract-drift.yml
@@ -17,10 +17,10 @@ jobs:
   drift:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6.0.3
 
       - name: Install uv
-        uses: astral-sh/setup-uv@v5
+        uses: astral-sh/setup-uv@fac544c07dec837d0ccb6301d7b5580bf5edae39 # v8.2.0
         with:
           python-version: "3.11"
 
diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index f480945..dba0a2b 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -7,8 +7,8 @@
 #   workflow = release.yml · environment = (leave blank)
 # Docs: https://docs.pypi.org/trusted-publishers/
 #
-# Hardening note: for production, pin the actions below to commit digests
-# (e.g. actions/checkout@<sha>) rather than moving tags.
+# Actions below are pinned to commit SHAs (version in the trailing comment) for
+# supply-chain safety — bump the SHA and comment together when updating.
 name: Publish
 
 on:
@@ -23,10 +23,10 @@ jobs:
     permissions:
       id-token: write        # required for OIDC trusted publishing
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6.0.3
 
       - name: Install uv
-        uses: astral-sh/setup-uv@v5
+        uses: astral-sh/setup-uv@fac544c07dec837d0ccb6301d7b5580bf5edae39 # v8.2.0
         with:
           python-version: "3.11"