diff --git a/.gitea/workflows/pipeline.yml b/.gitea/workflows/pipeline.yml
index 1e250e2..385a646 100644
--- a/.gitea/workflows/pipeline.yml
+++ b/.gitea/workflows/pipeline.yml
@@ -16,6 +16,7 @@ jobs:
   lint-php:
     name: PHP Lint (${{ matrix.php }})
     runs-on: ubuntu-latest
+    container: git.protopeer.com/peptide-repo/ci-php:2026-10
     strategy:
       fail-fast: false
       matrix:
@@ -29,6 +30,7 @@ jobs:
   phpcs:
     name: PHPCS (WordPress standards)
     runs-on: ubuntu-latest
+    container: git.protopeer.com/peptide-repo/ci-php:2026-10
     steps:
       - uses: actions/checkout@v4
         with:
@@ -41,6 +43,7 @@ jobs:
   file-size:
     name: 300-line rule (includes)
     runs-on: ubuntu-latest
+    container: git.protopeer.com/peptide-repo/ci-php:2026-10
     steps:
       - uses: actions/checkout@v4
       - uses: https://git.protopeer.com/peptide-repo/peptide-e2e/.gitea/actions/ci-file-size@main
@@ -50,6 +53,7 @@ jobs:
   phpunit:
     name: PHPUnit - brain-monkey (PHP ${{ matrix.php }})
     runs-on: ubuntu-latest
+    container: git.protopeer.com/peptide-repo/ci-php:2026-10
     strategy:
       fail-fast: false
       matrix:
@@ -64,12 +68,11 @@ jobs:
   check-constants:
     name: Check PRAUTOBLOGGER_* constants
     runs-on: ubuntu-latest
+    container: git.protopeer.com/peptide-repo/ci-php:2026-10
     steps:
       - uses: actions/checkout@v4
-      - uses: shivammathur/setup-php@v2
-        with:
-          php-version: '8.1'
-          coverage: none
+      - name: Use PHP 8.1 (preinstalled in the CI image)
+        run: update-alternatives --set php /usr/bin/php8.1 && php -v | head -1
       # Fails if any PRAUTOBLOGGER_* constant referenced in shipped PHP is neither
       # defined in prautoblogger.php nor guarded by defined() (v0.19.0 incident class).
       - run: php scripts/check-constants.php
@@ -125,6 +128,7 @@ jobs:
     name: Audit - commit came from a PR
     if: ${{ github.event_name == 'push' && github.ref == 'refs/heads/main' }}
     runs-on: ubuntu-latest
+    container: git.protopeer.com/peptide-repo/ci-php:2026-10
     steps:
       - uses: https://git.protopeer.com/peptide-repo/peptide-e2e/.gitea/actions/audit-direct-push@main
         with: