diff --git a/.github/workflows/CompatHelper.yml b/.github/workflows/CompatHelper.yml
index 6ec57028..420c2ced 100644
--- a/.github/workflows/CompatHelper.yml
+++ b/.github/workflows/CompatHelper.yml
@@ -6,7 +6,7 @@ on:
   workflow_dispatch:
 jobs:
   CompatHelper:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-slim
     steps:
       - name: Check if Julia is already available
         id: julia_in_path
diff --git a/.github/workflows/doc-preview-cleanup.yml b/.github/workflows/doc-preview-cleanup.yml
index f0863bcb..d7ca2b6f 100644
--- a/.github/workflows/doc-preview-cleanup.yml
+++ b/.github/workflows/doc-preview-cleanup.yml
@@ -6,7 +6,7 @@ on:
   workflow_dispatch:
 jobs:
   doc-preview-cleanup:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-slim
     steps:
       - name: Checkout gh-pages branch
         uses: actions/checkout@v6
diff --git a/.github/workflows/documentation.yml b/.github/workflows/documentation.yml
index 97440f62..ffb8993e 100644
--- a/.github/workflows/documentation.yml
+++ b/.github/workflows/documentation.yml
@@ -27,7 +27,7 @@ jobs:
       - name: Set up Julia
         uses: julia-actions/setup-julia@v2
         with:
-          version: '1'
+          version: '1.12.4'  # parser broken on 1.12.5
       - name: Check out repository
         uses: actions/checkout@v6
       - name: Cache artifacts
diff --git a/.github/workflows/format.yml b/.github/workflows/format.yml
index 9edb84f1..1c12b660 100644
--- a/.github/workflows/format.yml
+++ b/.github/workflows/format.yml
@@ -6,10 +6,12 @@ on:
   workflow_dispatch:
 jobs:
   format:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-slim
     steps:
       - name: Check out repository
         uses: actions/checkout@v6
+      - name: Set up Julia
+        uses: julia-actions/setup-julia@v2
       - name: Cache artifacts
         uses: julia-actions/cache@v2
       - name: Install JuliaFormatter and format
diff --git a/.github/workflows/invalidations.yml b/.github/workflows/invalidations.yml
index b773cffd..fe127a45 100644
--- a/.github/workflows/invalidations.yml
+++ b/.github/workflows/invalidations.yml
@@ -12,7 +12,7 @@ concurrency:
   cancel-in-progress: true
 jobs:
   evaluate:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-slim
     if: "!contains(github.event.head_commit.message, 'skip ci')"
     env:
       JULIA_PKG_SERVER: ''
diff --git a/.github/workflows/spell-check.yml b/.github/workflows/spell-check.yml
index 6488eff4..bc01c9db 100644
--- a/.github/workflows/spell-check.yml
+++ b/.github/workflows/spell-check.yml
@@ -9,7 +9,7 @@ concurrency:
   cancel-in-progress: true
 jobs:
   spell-check:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-slim
     if: "!contains(github.event.head_commit.message, 'skip ci')"
     steps:
       - name: Check out repository
diff --git a/.github/workflows/test-pull-request.yml b/.github/workflows/test-pull-request.yml
index 6cf8240a..75b6596c 100644
--- a/.github/workflows/test-pull-request.yml
+++ b/.github/workflows/test-pull-request.yml
@@ -28,7 +28,7 @@ jobs:
         include:
           - version: '1.6'  # test on oldest supported version
             arch: x64
-            os: ubuntu-latest
+            os: ubuntu-slim
     env:
       JULIA_PKG_SERVER: ''
     steps: