diff --git a/scripts/start_sandbox.sh b/scripts/start_sandbox.sh
index b17f1a7e..1c3e2417 100755
--- a/scripts/start_sandbox.sh
+++ b/scripts/start_sandbox.sh
@@ -56,6 +56,9 @@ done
 # copy GEMINI_API_KEY
 if [ -n "${GEMINI_API_KEY:-}" ]; then run_args+=(--env GEMINI_API_KEY="$GEMINI_API_KEY"); fi
 
+# copy GEMINI_CODE_MODEL
+if [ -n "${GEMINI_CODE_MODEL:-}" ]; then run_args+=(--env GEMINI_CODE_MODEL="$GEMINI_CODE_MODEL"); fi
+
 # copy SHELL_TOOL to optionally enable shell tool
 if [ -n "${SHELL_TOOL:-}" ]; then run_args+=(--env SHELL_TOOL="$SHELL_TOOL"); fi