diff --git a/.gcp/release-docker.yaml b/.gcp/release-docker.yaml
index 547c3c22ee..548e3cd38f 100644
--- a/.gcp/release-docker.yaml
+++ b/.gcp/release-docker.yaml
@@ -17,46 +17,48 @@ steps:
     entrypoint: 'npm'
     args: ['run', 'build:packages']
 
-  # Step 6: Build sandbox container image
+  # Step 6: Determine Docker Image Tag
+  - name: 'us-west1-docker.pkg.dev/gemini-code-dev/gemini-code-containers/gemini-code-builder'
+    id: 'Determine Docker Image Tag'
+    entrypoint: 'bash'
+    args:
+      - -c
+      - |
+        IMAGE_TAG="$SHORT_SHA" # Default to SHA
+        if [[ "$TAG_NAME" == *"+nightly"* ]]; then
+          echo "Nightly release detected."
+          IMAGE_TAG="${TAG_NAME#v}"
+        elif [[ "$TAG_NAME" =~ ^v[0-9]+\.[0-9]+\.[0-9]+$ ]]; then
+          echo "Official release detected."
+          IMAGE_TAG="${TAG_NAME#v}"
+        else
+          echo "Development/RC release detected. Using commit SHA as tag."
+        fi
+        echo "Determined image tag: $IMAGE_TAG"
+        echo "$IMAGE_TAG" > /workspace/image_tag.txt
+
+  # Step 7: Build sandbox container image
   - name: 'us-west1-docker.pkg.dev/gemini-code-dev/gemini-code-containers/gemini-code-builder'
     id: 'Build sandbox Docker image'
     entrypoint: 'bash'
     args:
       - -c
       - |
-        export GEMINI_SANDBOX_IMAGE_TAG="$SHORT_SHA" # Default to SHA
-        if [[ "$TAG_NAME" == *"+nightly"* ]]; then
-          echo "Nightly release detected."
-          export GEMINI_SANDBOX_IMAGE_TAG="${TAG_NAME#v}"
-        elif [[ "$TAG_NAME" =~ ^v[0-9]+\.[0-9]+\.[0-9]+$ ]]; then
-          echo "Official release detected."
-          export GEMINI_SANDBOX_IMAGE_TAG="${TAG_NAME#v}"
-        else
-          echo "Development/RC release detected. Using commit SHA as tag."
-        fi
-        echo "Using Docker image tag: $GEMINI_SANDBOX_IMAGE_TAG"
+        export GEMINI_SANDBOX_IMAGE_TAG=$(cat /workspace/image_tag.txt)
+        echo "Using Docker image tag for build: $GEMINI_SANDBOX_IMAGE_TAG"
         npm run build:sandbox:fast
     env:
       - 'GEMINI_SANDBOX=$_CONTAINER_TOOL'
 
-  # Step 7: Publish sandbox container image
+  # Step 8: Publish sandbox container image
   - name: 'us-west1-docker.pkg.dev/gemini-code-dev/gemini-code-containers/gemini-code-builder'
     id: 'Publish sandbox Docker image'
     entrypoint: 'bash'
     args:
       - -c
       - |
-        export GEMINI_SANDBOX_IMAGE_TAG="$SHORT_SHA" # Default to SHA
-        if [[ "$TAG_NAME" == *"+nightly"* ]]; then
-          echo "Nightly release detected."
-          export GEMINI_SANDBOX_IMAGE_TAG="${TAG_NAME#v}"
-        elif [[ "$TAG_NAME" =~ ^v[0-9]+\.[0-9]+\.[0-9]+$ ]]; then
-          echo "Official release detected."
-          export GEMINI_SANDBOX_IMAGE_TAG="${TAG_NAME#v}"
-        else
-          echo "Development/RC release detected. Using commit SHA as tag."
-        fi
-        echo "Using Docker image tag: $GEMINI_SANDBOX_IMAGE_TAG"
+        export GEMINI_SANDBOX_IMAGE_TAG=$(cat /workspace/image_tag.txt)
+        echo "Using Docker image tag for publish: $GEMINI_SANDBOX_IMAGE_TAG"
         npm run publish:sandbox
     env:
       - 'GEMINI_SANDBOX=$_CONTAINER_TOOL'