diff --git a/.github/workflows/changelog.yml b/.github/workflows/changelog.yml
index 297048284b6..113643b4bde 100644
--- a/.github/workflows/changelog.yml
+++ b/.github/workflows/changelog.yml
@@ -15,6 +15,8 @@ jobs:
 
     steps:
       - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+        with:
+          persist-credentials: false
 
       - name: Grep CHANGES.md for PR number
         if: contains(github.event.pull_request.labels.*.name, 'skip news') != true
diff --git a/.github/workflows/diff_shades.yml b/.github/workflows/diff_shades.yml
index 4cc3670bc59..0683dda8711 100644
--- a/.github/workflows/diff_shades.yml
+++ b/.github/workflows/diff_shades.yml
@@ -18,6 +18,8 @@ env:
   # binaries too).
   CC: clang-18
 
+permissions: {}
+
 jobs:
   configure:
     runs-on: ubuntu-latest
@@ -26,6 +28,8 @@ jobs:
 
     steps:
       - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+        with:
+          persist-credentials: false
 
       - uses: actions/setup-python@83679a892e2d95755f2dac6acb0bfd1e9ac5d548 # v6.1.0
         with:
@@ -57,6 +61,7 @@ jobs:
         with:
           # The baseline revision could be rather old so a full clone is ideal.
           fetch-depth: 0
+          persist-credentials: false
 
       - uses: actions/setup-python@83679a892e2d95755f2dac6acb0bfd1e9ac5d548 # v6.1.0
         with:
@@ -110,6 +115,7 @@ jobs:
         with:
           # The baseline revision could be rather old so a full clone is ideal.
           fetch-depth: 0
+          persist-credentials: false
 
       - uses: actions/setup-python@83679a892e2d95755f2dac6acb0bfd1e9ac5d548 # v6.1.0
         with:
@@ -172,6 +178,8 @@ jobs:
 
     steps:
       - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+        with:
+          persist-credentials: false
 
       - uses: actions/download-artifact@018cc2cf5baa6db3ef3c5f8a56943fffe632ef53 # v6.0.0
         with:
diff --git a/.github/workflows/diff_shades_comment.yml b/.github/workflows/diff_shades_comment.yml
index f58c11382c8..30de91112bd 100644
--- a/.github/workflows/diff_shades_comment.yml
+++ b/.github/workflows/diff_shades_comment.yml
@@ -5,14 +5,17 @@ on:
     workflows: [diff-shades]
     types: [completed]
 
-permissions:
-  pull-requests: write
+permissions: {}
 
 jobs:
   comment:
     runs-on: ubuntu-latest
+    permissions:
+      pull-requests: write
     steps:
       - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+        with:
+          persist-credentials: false
       - uses: actions/setup-python@83679a892e2d95755f2dac6acb0bfd1e9ac5d548 # v6.1.0
         with:
           python-version: "3.13"
diff --git a/.github/workflows/doc.yml b/.github/workflows/doc.yml
index 359e70f975b..1aa154fdbc5 100644
--- a/.github/workflows/doc.yml
+++ b/.github/workflows/doc.yml
@@ -27,6 +27,8 @@ jobs:
     runs-on: ${{ matrix.os }}
     steps:
       - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+        with:
+          persist-credentials: false
 
       - name: Set up latest Python
         uses: actions/setup-python@83679a892e2d95755f2dac6acb0bfd1e9ac5d548 # v6.1.0
diff --git a/.github/workflows/docker.yml b/.github/workflows/docker.yml
index 3a362a86aca..ed52f4a131d 100644
--- a/.github/workflows/docker.yml
+++ b/.github/workflows/docker.yml
@@ -17,6 +17,8 @@ jobs:
     steps:
       - name: Checkout
         uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0
+        with:
+          persist-credentials: false
 
       - name: Set up QEMU
         uses: docker/setup-qemu-action@c7c53464625b32c7a7e944ae62b3e17d2b600130 # v3.7.0
diff --git a/.github/workflows/fuzz.yml b/.github/workflows/fuzz.yml
index 68527b3af73..941507175f2 100644
--- a/.github/workflows/fuzz.yml
+++ b/.github/workflows/fuzz.yml
@@ -35,6 +35,8 @@ jobs:
 
     steps:
       - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+        with:
+          persist-credentials: false
 
       - name: Set up Python ${{ matrix.python-version }}
         uses: actions/setup-python@83679a892e2d95755f2dac6acb0bfd1e9ac5d548 # v6.1.0
diff --git a/.github/workflows/lint.yml b/.github/workflows/lint.yml
index 180f9da5156..d5a9e99f6be 100644
--- a/.github/workflows/lint.yml
+++ b/.github/workflows/lint.yml
@@ -2,6 +2,8 @@ name: Lint + format ourselves
 
 on: [push, pull_request]
 
+permissions: {}
+
 jobs:
   build:
     # We want to run on external PRs, but not on our own internal PRs as they'll be run
@@ -15,6 +17,8 @@ jobs:
 
     steps:
       - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+        with:
+          persist-credentials: false
 
       - name: Assert PR target is main
         if: github.event_name == 'pull_request' && github.repository == 'psf/black'
diff --git a/.github/workflows/pypi_upload.yml b/.github/workflows/pypi_upload.yml
index 7d6ade2961e..2c853ca0462 100644
--- a/.github/workflows/pypi_upload.yml
+++ b/.github/workflows/pypi_upload.yml
@@ -19,6 +19,8 @@ jobs:
 
     steps:
       - uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0
+        with:
+          persist-credentials: false
 
       - name: Set up latest Python
         uses: actions/setup-python@83679a892e2d95755f2dac6acb0bfd1e9ac5d548 # v6.1.0
@@ -47,6 +49,8 @@ jobs:
       include: ${{ steps.set-matrix.outputs.include }}
     steps:
       - uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0
+        with:
+          persist-credentials: false
       # Keep cibuildwheel version in sync with below
       - name: Install cibuildwheel and pypyp
         run: |
@@ -94,6 +98,8 @@ jobs:
 
     steps:
       - uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0
+        with:
+          persist-credentials: false
       # Keep cibuildwheel version in sync with above
       - uses: pypa/cibuildwheel@63fd63b352a9a8bdcc24791c9dbee952ee9a8abc # v3.3.0
         with:
@@ -125,6 +131,7 @@ jobs:
         with:
           ref: stable
           fetch-depth: 0
+          persist-credentials: true # needed for `git push` below
 
       - if: github.event_name == 'release'
         name: Update stable branch to release tag & push
diff --git a/.github/workflows/release_tests.yml b/.github/workflows/release_tests.yml
index 64f478f1ded..cf095804529 100644
--- a/.github/workflows/release_tests.yml
+++ b/.github/workflows/release_tests.yml
@@ -12,6 +12,8 @@ on:
       - release.py
       - release_tests.py
 
+permissions: {}
+
 jobs:
   build:
     # We want to run on external PRs, but not on our own internal PRs as they'll be run
@@ -33,6 +35,7 @@ jobs:
         with:
           # Give us all history, branches and tags
           fetch-depth: 0
+          persist-credentials: false
       - name: Set up Python ${{ matrix.python-version }}
         uses: actions/setup-python@83679a892e2d95755f2dac6acb0bfd1e9ac5d548 # v6.1.0
         with:
diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index bf9b12c7f0b..129cee7f034 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -42,6 +42,8 @@ jobs:
 
     steps:
       - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+        with:
+          persist-credentials: false
 
       - name: Set up Python ${{ matrix.python-version }}
         uses: actions/setup-python@83679a892e2d95755f2dac6acb0bfd1e9ac5d548 # v6.1.0
@@ -83,6 +85,8 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+        with:
+          persist-credentials: false
       - name: Send finished signal to Coveralls
         uses: AndreMiras/coveralls-python-action@ac868b9540fad490f7ca82b8ca00480fd751ed19
         with:
@@ -101,6 +105,8 @@ jobs:
 
     steps:
       - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+        with:
+          persist-credentials: false
 
       - name: Set up latest Python
         uses: actions/setup-python@83679a892e2d95755f2dac6acb0bfd1e9ac5d548 # v6.1.0
diff --git a/.github/workflows/upload_binary.yml b/.github/workflows/upload_binary.yml
index 3795b493970..7c6a6d3d958 100644
--- a/.github/workflows/upload_binary.yml
+++ b/.github/workflows/upload_binary.yml
@@ -38,6 +38,8 @@ jobs:
 
     steps:
       - uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0
+        with:
+          persist-credentials: false
 
       - name: Set up latest Python
         uses: actions/setup-python@83679a892e2d95755f2dac6acb0bfd1e9ac5d548 # v6.1.0