diff --git a/.github/workflows/deploy-docs.yml b/.github/workflows/deploy-docs.yml
index d936801..850c11c 100644
--- a/.github/workflows/deploy-docs.yml
+++ b/.github/workflows/deploy-docs.yml
@@ -6,8 +6,13 @@ jobs:
   deploy-docs:
     runs-on: ubuntu-latest
     steps:
+      - name: Harden the runner (Audit all outbound calls)
+        uses: step-security/harden-runner@0634a2670c59f64b4a01f0f96f84700a4088b9f0 # v2.12.0
+        with:
+          egress-policy: audit
+
       - name: Check out
-        uses: actions/checkout@v4
+        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
 
       - name: Set up the environment
         uses: ./.github/actions/setup-poetry-env
diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index e6ca367..485c21f 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -11,10 +11,15 @@ jobs:
   quality:
     runs-on: ubuntu-latest
     steps:
+      - name: Harden the runner (Audit all outbound calls)
+        uses: step-security/harden-runner@0634a2670c59f64b4a01f0f96f84700a4088b9f0 # v2.12.0
+        with:
+          egress-policy: audit
+
       - name: Check out
-        uses: actions/checkout@v4
+        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
 
-      - uses: actions/cache@v4
+      - uses: actions/cache@5a3ec84eff668545956fd18022155c47e93e2684 # v4.2.3
         with:
           path: ~/.cache/pre-commit
           key: pre-commit-${{ hashFiles('.pre-commit-config.yaml') }}
@@ -35,8 +40,13 @@ jobs:
       run:
         shell: bash
     steps:
+      - name: Harden the runner (Audit all outbound calls)
+        uses: step-security/harden-runner@0634a2670c59f64b4a01f0f96f84700a4088b9f0 # v2.12.0
+        with:
+          egress-policy: audit
+
       - name: Check out
-        uses: actions/checkout@v4
+        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
 
       - name: Set up the environment
         uses: ./.github/actions/setup-poetry-env
@@ -53,14 +63,19 @@ jobs:
         run: poetry run pyright
 
       - name: Upload coverage reports to Codecov with GitHub Action on Python 3.13
-        uses: codecov/codecov-action@v4
+        uses: codecov/codecov-action@b9fd7d16f6d7d1b5d2bec1a2887e65ceed900238 # v4.6.0
         if: ${{ matrix.python-version == '3.13' }}
 
   check-docs:
     runs-on: ubuntu-latest
     steps:
+      - name: Harden the runner (Audit all outbound calls)
+        uses: step-security/harden-runner@0634a2670c59f64b4a01f0f96f84700a4088b9f0 # v2.12.0
+        with:
+          egress-policy: audit
+
       - name: Check out
-        uses: actions/checkout@v4
+        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
 
       - name: Set up the environment
         uses: ./.github/actions/setup-poetry-env
diff --git a/.github/workflows/on-release-main.yml b/.github/workflows/on-release-main.yml
index 080026d..ceb56e7 100644
--- a/.github/workflows/on-release-main.yml
+++ b/.github/workflows/on-release-main.yml
@@ -9,8 +9,13 @@ jobs:
   publish:
     runs-on: ubuntu-latest
     steps:
+      - name: Harden the runner (Audit all outbound calls)
+        uses: step-security/harden-runner@0634a2670c59f64b4a01f0f96f84700a4088b9f0 # v2.12.0
+        with:
+          egress-policy: audit
+
       - name: Check out
-        uses: actions/checkout@v4
+        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
 
       - name: Set up the environment
         uses: ./.github/actions/setup-poetry-env
@@ -31,8 +36,13 @@ jobs:
     needs: publish
     runs-on: ubuntu-latest
     steps:
+      - name: Harden the runner (Audit all outbound calls)
+        uses: step-security/harden-runner@0634a2670c59f64b4a01f0f96f84700a4088b9f0 # v2.12.0
+        with:
+          egress-policy: audit
+
       - name: Check out
-        uses: actions/checkout@v4
+        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
 
       - name: Set up the environment
         uses: ./.github/actions/setup-poetry-env
diff --git a/.github/workflows/validate-codecov-config.yml b/.github/workflows/validate-codecov-config.yml
index 2a8fd11..57877fd 100644
--- a/.github/workflows/validate-codecov-config.yml
+++ b/.github/workflows/validate-codecov-config.yml
@@ -6,10 +6,18 @@ on:
   push:
     branches: [main]
 
+permissions:
+  contents: read
+
 jobs:
   validate-codecov-config:
     runs-on: ubuntu-22.04
     steps:
-      - uses: actions/checkout@v4
+      - name: Harden the runner (Audit all outbound calls)
+        uses: step-security/harden-runner@0634a2670c59f64b4a01f0f96f84700a4088b9f0 # v2.12.0
+        with:
+          egress-policy: audit
+
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
       - name: Validate codecov configuration
         run: curl -sSL --fail-with-body --data-binary @codecov.yaml https://codecov.io/validate