diff --git a/src/optima35/__main__.py b/src/optima35/__main__.py
new file mode 100644
index 0000000..5eee31f
--- /dev/null
+++ b/src/optima35/__main__.py
@@ -0,0 +1,8 @@
+from . import __version__
+
+def main():
+    print(f"optima35 (v{__version__}) is a core library and not intended to be run directly.")
+    print("Please use OptimaLab35 for a UI, run pip install OptimaLab35 and start with OptimaLab35.")
+
+if __name__ == "__main__":
+    main()