diff --git a/.woodpecker/build.yaml b/.woodpecker/build.yaml
index ef4fb6c..d18fdb8 100644
--- a/.woodpecker/build.yaml
+++ b/.woodpecker/build.yaml
@@ -12,8 +12,9 @@ steps:
           password: {from_secret: kokuwa_io_password}
       platform: [linux/amd64, linux/arm64]
       build-args:
-        NPM_CONFIG_REGISTRY: $NPM_CONFIG_REGISTRY
+        NPM_CONFIG_REGISTRY:
         FOO: bar 
+        CCC: null 
       annotation:
         org.opencontainers.image.title: Buildctl WoodpeckerCI Plugin
         org.opencontainers.image.description: A WoodpeckerCI plugin for buildctl to build container images using a remote builtkitd instance.