diff --git a/.gitea/workflows/build-ci-image.yml b/.gitea/workflows/build-ci-image.yml
index d5333a5..962f11d 100644
--- a/.gitea/workflows/build-ci-image.yml
+++ b/.gitea/workflows/build-ci-image.yml
@@ -8,6 +8,10 @@ on:
       - .gitea/workflows/build-ci-image.yml
   workflow_dispatch:
 
+env:
+  REGISTRY_HOST: git.neosisyphus.com
+  REGISTRY_IMAGE: git.neosisyphus.com/evol3d/evol-testbed
+
 jobs:
   image:
     runs-on: ubuntu-latest
@@ -17,7 +21,7 @@ jobs:
 
       - name: Log in to container registry
         run: |
-          echo "${{ secrets.REGISTRY_PASSWORD }}" | docker login "${{ vars.REGISTRY_HOST }}" \
+          echo "${{ secrets.REGISTRY_PASSWORD }}" | docker login "$REGISTRY_HOST" \
             -u "${{ secrets.REGISTRY_USERNAME }}" \
             --password-stdin
 
@@ -27,11 +31,11 @@ jobs:
             --build-arg BASE_IMAGE=catthehacker/ubuntu:act-latest \
             --build-arg LLVM_VERSION=22 \
             --build-arg MESON_VERSION=latest \
-            -t "${{ vars.REGISTRY_IMAGE }}:latest" \
-            -t "${{ vars.REGISTRY_IMAGE }}:clang22" \
+            -t "$REGISTRY_IMAGE:latest" \
+            -t "$REGISTRY_IMAGE:clang22" \
             -f ci/Dockerfile .
 
       - name: Push CI image
         run: |
-          docker push "${{ vars.REGISTRY_IMAGE }}:latest"
-          docker push "${{ vars.REGISTRY_IMAGE }}:clang22"
+          docker push "$REGISTRY_IMAGE:latest"
+          docker push "$REGISTRY_IMAGE:clang22"
diff --git a/.gitea/workflows/build.yml b/.gitea/workflows/build.yml
index 7d1b5eb..a7237e1 100644
--- a/.gitea/workflows/build.yml
+++ b/.gitea/workflows/build.yml
@@ -1,17 +1,17 @@
 name: build
 
+# This is a manual smoke-test for the already-published image.
+# Do not run it on every push in this image repository, because the first push
+# happens before the image exists in the registry.
 on:
-  push:
-  pull_request:
+  workflow_dispatch:
 
 jobs:
   linux:
     runs-on: ubuntu-latest
 
-    # Set vars.CI_IMAGE to the same value as vars.REGISTRY_IMAGE, or replace this
-    # line with your full image path, e.g. git.neosisyphus.com/evol3d/evol-testbed:clang22
     container:
-      image: ${{ vars.CI_IMAGE }}:clang22
+      image: git.neosisyphus.com/evol3d/evol-testbed:clang22
 
     steps:
       - uses: actions/checkout@v4