diff --git a/tools/update-nixpkgs b/tools/update-nixpkgs
index 3c6832c95cee09632318f7a4ef4efc7099e317e1..12752892fab880582857d43c5cc4632a41c96d0f 100755
--- a/tools/update-nixpkgs
+++ b/tools/update-nixpkgs
@@ -49,7 +49,9 @@ def main():
     args = parser.parse_args()
 
     repo_file = args.repo_file
+    print(f"reading {repo_file}")
     config = json.loads(repo_file.read_text())
+    print(f"read {config!r}")
 
     config["url"] = get_nixos_channel_url(channel=args.channel)
     hash_data = get_url_hash(HASH_TYPE, name=config["name"], url=config["url"])
@@ -59,6 +61,7 @@ def main():
     if args.dry_run:
         print(output)
     else:
+        print(f"writing to {repo_file}")
         repo_file.write_text(output)