diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 6079fdc4..848cd620 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -43,13 +43,12 @@ deploy_to_test:
 oci_calculator:
   # A convenient way for users to run the CARA calculator.
   stage: deploy
+  rules:
+    # Only run if branch is master (the default branch).
+    - if: $CI_COMMIT_REF_NAME == $CI_DEFAULT_BRANCH   
   image:
         name: gitlab-registry.cern.ch/ci-tools/docker-image-builder
         entrypoint: [""]
   script:
-        # Prepare Kaniko configuration file
         - echo "{\"auths\":{\"$CI_REGISTRY\":{\"username\":\"$CI_REGISTRY_USER\",\"password\":\"$CI_REGISTRY_PASSWORD\"}}}" > /kaniko/.docker/config.json
-        # Build and push the image from the Dockerfile at the root of the project.
-        # To push to a specific docker tag, amend the --destination parameter, e.g. --destination $CI_REGISTRY_IMAGE:$CI_BUILD_REF_NAME
-        # See https://docs.gitlab.com/ee/ci/variables/predefined_variables.html#variables-reference for available variables
         - /kaniko/executor --context $CI_PROJECT_DIR --dockerfile $CI_PROJECT_DIR/Dockerfile --destination $CI_REGISTRY_IMAGE/calculator:latest