diff --git a/.github/workflows/guix-nix-policy.yml b/.github/workflows/guix-nix-policy.yml
index 6771253..b2d87cb 100644
--- a/.github/workflows/guix-nix-policy.yml
+++ b/.github/workflows/guix-nix-policy.yml
@@ -4,7 +4,7 @@ jobs:
   check:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v6.0.1
       - name: Enforce Guix primary / Nix fallback
         run: |
           # Check for package manager files
diff --git a/.github/workflows/jekyll-gh-pages.yml b/.github/workflows/jekyll-gh-pages.yml
index e729658..9a62b2e 100644
--- a/.github/workflows/jekyll-gh-pages.yml
+++ b/.github/workflows/jekyll-gh-pages.yml
@@ -27,7 +27,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v6
+        uses: actions/checkout@v6.0.1
       - name: Setup Pages
         uses: actions/configure-pages@v5
       - name: Build with Jekyll
diff --git a/.github/workflows/npm-bun-blocker.yml b/.github/workflows/npm-bun-blocker.yml
index d4f73fc..1f8fe05 100644
--- a/.github/workflows/npm-bun-blocker.yml
+++ b/.github/workflows/npm-bun-blocker.yml
@@ -4,7 +4,7 @@ jobs:
   check:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v6.0.1
       - name: Block npm/bun
         run: |
           if [ -f "package-lock.json" ] || [ -f "bun.lockb" ] || [ -f ".npmrc" ]; then
diff --git a/.github/workflows/quality.yml b/.github/workflows/quality.yml
index c1a7b7a..56d5585 100644
--- a/.github/workflows/quality.yml
+++ b/.github/workflows/quality.yml
@@ -5,7 +5,7 @@ jobs:
   lint:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v6.0.1
       
       - name: Check file permissions
         run: |
@@ -35,7 +35,7 @@ jobs:
   docs:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v6.0.1
       - name: Check documentation
         run: |
           MISSING=""
diff --git a/.github/workflows/rescript-deno-ci.yml b/.github/workflows/rescript-deno-ci.yml
index 6274eae..91cf283 100644
--- a/.github/workflows/rescript-deno-ci.yml
+++ b/.github/workflows/rescript-deno-ci.yml
@@ -5,7 +5,7 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v6.0.1
       - uses: denoland/setup-deno@v1
         with:
           deno-version: v1.x
@@ -32,7 +32,7 @@ jobs:
   security:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v6.0.1
       - uses: denoland/setup-deno@v1
       - name: Check permissions
         run: |
diff --git a/.github/workflows/rsr-antipattern.yml b/.github/workflows/rsr-antipattern.yml
index e6ce6a0..964c51c 100644
--- a/.github/workflows/rsr-antipattern.yml
+++ b/.github/workflows/rsr-antipattern.yml
@@ -16,7 +16,7 @@ jobs:
   antipattern-check:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v6.0.1
 
       - name: Check for TypeScript
         run: |
diff --git a/.github/workflows/scorecard-enforcer.yml b/.github/workflows/scorecard-enforcer.yml
index 9462271..0602b18 100644
--- a/.github/workflows/scorecard-enforcer.yml
+++ b/.github/workflows/scorecard-enforcer.yml
@@ -18,7 +18,7 @@ jobs:
       security-events: write
       id-token: write  # For OIDC
     steps:
-      - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # v4
+      - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v4
         with:
           persist-credentials: false
 
@@ -53,7 +53,7 @@ jobs:
   check-critical:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # v4
+      - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v4
 
       - name: Check SECURITY.md exists
         run: |
diff --git a/.github/workflows/scorecard.yml b/.github/workflows/scorecard.yml
index c1071e6..b9a7175 100644
--- a/.github/workflows/scorecard.yml
+++ b/.github/workflows/scorecard.yml
@@ -14,7 +14,7 @@ jobs:
       security-events: write
       id-token: write
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v6.0.1
         with:
           persist-credentials: false
       
diff --git a/.github/workflows/secret-scanner.yml b/.github/workflows/secret-scanner.yml
index e3578aa..fadf342 100644
--- a/.github/workflows/secret-scanner.yml
+++ b/.github/workflows/secret-scanner.yml
@@ -13,7 +13,7 @@ jobs:
   trufflehog:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # v4
+      - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v4
         with:
           fetch-depth: 0  # Full history for scanning
 
@@ -25,7 +25,7 @@ jobs:
   gitleaks:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # v4
+      - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v4
         with:
           fetch-depth: 0
 
@@ -39,7 +39,7 @@ jobs:
     runs-on: ubuntu-latest
     if: hashFiles('**/Cargo.toml') != ''
     steps:
-      - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # v4
+      - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v4
 
       - name: Check for hardcoded secrets in Rust
         run: |
diff --git a/.github/workflows/security-policy.yml b/.github/workflows/security-policy.yml
index a9d7c0f..ed1b4f9 100644
--- a/.github/workflows/security-policy.yml
+++ b/.github/workflows/security-policy.yml
@@ -4,7 +4,7 @@ jobs:
   check:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v6.0.1
       - name: Security checks
         run: |
           FAILED=false
diff --git a/.github/workflows/ts-blocker.yml b/.github/workflows/ts-blocker.yml
index f31b6cc..4886053 100644
--- a/.github/workflows/ts-blocker.yml
+++ b/.github/workflows/ts-blocker.yml
@@ -4,7 +4,7 @@ jobs:
   check:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v6.0.1
       - name: Block new TypeScript/JavaScript
         run: |
           NEW_TS=$(git diff --name-only --diff-filter=A HEAD~1 2>/dev/null | grep -E '\.(ts|tsx)$' | grep -v '\.gen\.' || true)
diff --git a/.github/workflows/wellknown-enforcement.yml b/.github/workflows/wellknown-enforcement.yml
index 2108364..af2216d 100644
--- a/.github/workflows/wellknown-enforcement.yml
+++ b/.github/workflows/wellknown-enforcement.yml
@@ -17,7 +17,7 @@ jobs:
   validate:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v6.0.1
       
       - name: RFC 9116 security.txt validation
         run: |