diff --git a/Dockerfile b/Dockerfile
index d813ef2..f6f260c 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -2,10 +2,10 @@
 #
 # Spark Executor MCP — runtime image.
 # Build deps with uv (frozen, prod-only), then drop in the source on top of
-# python:3.12-slim with Spark + YARN configs mounted for the spark-submit /
+# ppython:3.12-slim-bookworm with Spark + YARN configs mounted for the spark-submit /
 # yarn CLI calls inside the MCP tools.
 
-FROM python:3.12-slim
+FROM python:3.12-slim-bookworm
 
 # --- uv (official binary) ---
 COPY --from=ghcr.io/astral-sh/uv:latest /uv /uvx /usr/local/bin/