diff --git a/.github/workflows/install-smoke.yml b/.github/workflows/install-smoke.yml
index 5c2fa315107..319d22b1735 100644
--- a/.github/workflows/install-smoke.yml
+++ b/.github/workflows/install-smoke.yml
@@ -96,6 +96,8 @@ jobs:
           OPENCLAW_QR_SMOKE_FORCE_INSTALL: "1"
         run: bash scripts/e2e/qr-import-docker.sh
 
+      # Build once with the matrix extension and tag both smoke names. This
+      # keeps the build-arg coverage without a second Blacksmith build action.
       - name: Build root Dockerfile smoke image
         uses: useblacksmith/build-push-action@cbd1f60d194a98cb3be5523b15134501eaf0fbf3 # v2
         with:
@@ -103,7 +105,10 @@ jobs:
           file: ./Dockerfile
           build-args: |
             OPENCLAW_DOCKER_APT_UPGRADE=0
-          tags: openclaw-dockerfile-smoke:local
+            OPENCLAW_EXTENSIONS=matrix
+          tags: |
+            openclaw-dockerfile-smoke:local
+            openclaw-ext-smoke:local
           load: true
           push: false
           provenance: false
@@ -118,22 +123,6 @@ jobs:
           OPENCLAW_GATEWAY_NETWORK_E2E_SKIP_BUILD: "1"
         run: bash scripts/e2e/gateway-network-docker.sh
 
-      # This smoke validates that the build-arg path preinstalls the matrix
-      # runtime deps declared by the plugin and that matrix discovery stays
-      # healthy in the final runtime image.
-      - name: Build extension Dockerfile smoke image
-        uses: useblacksmith/build-push-action@cbd1f60d194a98cb3be5523b15134501eaf0fbf3 # v2
-        with:
-          context: .
-          file: ./Dockerfile
-          build-args: |
-            OPENCLAW_DOCKER_APT_UPGRADE=0
-            OPENCLAW_EXTENSIONS=matrix
-          tags: openclaw-ext-smoke:local
-          load: true
-          push: false
-          provenance: false
-
       - name: Smoke test Dockerfile with matrix extension build arg
         run: |
           docker run --rm --entrypoint sh openclaw-ext-smoke:local -lc '