diff --git a/pkgs/by-name/op/opentimestamps-client/package.nix b/pkgs/by-name/op/opentimestamps-client/package.nix
index fcb4c7a0851a..bb563188ca97 100644
--- a/pkgs/by-name/op/opentimestamps-client/package.nix
+++ b/pkgs/by-name/op/opentimestamps-client/package.nix
@@ -33,6 +33,7 @@ python3.pkgs.buildPythonApplication rec {
 
   meta = with lib; {
     description = "Command-line tool to create and verify OpenTimestamps proofs";
+    mainProgram = "ots";
     homepage = "https://github.com/opentimestamps/opentimestamps-client";
     changelog = "https://github.com/opentimestamps/opentimestamps-client/releases/tag/opentimestamps-client-v${version}";
     license = licenses.lgpl3Only;