diff --git a/check-iree-commit.sh b/check-iree-commit.sh
index f466e11..5119956 100755
--- a/check-iree-commit.sh
+++ b/check-iree-commit.sh
@@ -17,10 +17,13 @@
 # Check IREE runtime commit version to be consistent with the compiler.
 
 IREE_SRC="$1"
-IREE_COMPILER_DIR="$2"
 
-if [[ $# -ne 2 ]]; then
-  echo "Usage: check-iree-commit.sh <iree source dir> <iree compiler dir>"
+if [[ -z "${IREE_COMPILER_DIR}" ]]; then
+  echo "Source build/setup.sh first"
+  exit 1
+fi
+if [[ -z "${IREE_SRC}" ]]; then
+  echo "Usage: check-iree-commit.sh <iree source dir>"
   exit 1
 fi
 
diff --git a/download_iree_compiler.py b/download_iree_compiler.py
index 3cf814d..3be06a8 100755
--- a/download_iree_compiler.py
+++ b/download_iree_compiler.py
@@ -46,6 +46,12 @@
 
 def main():
     """ Download IREE host compiler from the snapshot release."""
+    iree_compiler_dir = os.getenv("IREE_COMPILER_DIR")
+    if not iree_compiler_dir:
+        print("Please run 'source build/setup.sh' first")
+        sys.exit(1)
+    iree_compiler_dir = Path(iree_compiler_dir)
+
     parser = argparse.ArgumentParser(
         description="Download IREE host compiler from snapshot releases")
     parser.add_argument(
@@ -57,15 +63,8 @@
         help=("URL to check the IREE release."
               "(default: https://api.github.com/repos/google/iree/releases)")
     )
-    parser.add_argument(
-        "--iree_compiler_dir", action="store", required=True,
-        default="",
-        help=("IREE compiler installed directory")
-    )
     args = parser.parse_args()
 
-    iree_compiler_dir = Path(args.iree_compiler_dir)
-
     snapshot = None
     if args.tag_name:
         r = requests.get((f"{args.release_url}/tags/{args.tag_name}"),