diff --git a/.github/workflows/_build-variant.yml b/.github/workflows/_build-variant.yml
index 0a6791b..3d6b462 100644
--- a/.github/workflows/_build-variant.yml
+++ b/.github/workflows/_build-variant.yml
@@ -82,6 +82,18 @@ jobs:
       - name: 'Checkout GitHub Action'
         uses: actions/checkout@v4
 
+      # Callers pass the raw Git ref/tag (e.g. `v1.1.2`, `v1.1.2a-pre.1`)
+      # or the literal `dev`. The leading `v` is a Git tag/GitHub release
+      # convention only — it must not leak into the Docker Hub tag or the
+      # in-container MADSCIENCELAB_VERSION banner, both of which follow
+      # this repo's pre-existing no-`v` version convention (e.g. `1.1.2a`).
+      - name: 'Compute image version (strip leading v)'
+        id: version
+        shell: bash
+        run: echo "value=${INPUT_VERSION#v}" >> "$GITHUB_OUTPUT"
+        env:
+          INPUT_VERSION: ${{ inputs.version }}
+
       - name: 'Set up Ruby for generation tool'
         uses: ruby/setup-ruby@v1
         with:
@@ -102,7 +114,7 @@ jobs:
 
       - name: 'Run file generation'
         id: file-gen
-        run: bash build.sh ${{ inputs.dir_args }} --version ${{ inputs.version }}
+        run: bash build.sh ${{ inputs.dir_args }} --version ${{ steps.version.outputs.value }}
 
       - name: 'Set up Docker Buildx'
         uses: docker/setup-buildx-action@v3
@@ -139,11 +151,11 @@ jobs:
           context: .
           file: ${{ inputs.image_dir }}/docker/Dockerfile
           build-args: |
-            CONTAINER_VERSION=${{ inputs.version }}
+            CONTAINER_VERSION=${{ steps.version.outputs.value }}
             IMAGE_NAME=${{ inputs.image_name }}
           push: ${{ inputs.push }}
           tags: |
-            ${{ env.IMAGE_URL }}:${{ inputs.version }}
+            ${{ env.IMAGE_URL }}:${{ steps.version.outputs.value }}
             ${{ env.IMAGE_URL }}:latest
           # Connect Docker driver to GitHub Action cache service
           cache-from: type=gha