diff --git a/runner/build.sh b/runner/build.sh
index 02e89c9..1a685a4 100755
--- a/runner/build.sh
+++ b/runner/build.sh
@@ -12,4 +12,11 @@ then
 else
     # c/c++ can be compiled directly by emcc
     emcc $file -Os -s WASM=1 -s SIDE_MODULE=1 -o out/contract.wasm
-fi
\ No newline at end of file
+fi
+
+if [ ! -f ./../gas/target/release/gas ] && [ ! -f ./../gas/target/release/gas.exe ] then
+    echo "No gas utility, compile it in /gas folder with"
+    echo "cargo build --release"    
+fi
+
+./../gas/target/release/gas ./out/contract.wasm ./out/contract.wasm
\ No newline at end of file