diff --git a/pkgs/applications/misc/rtfm/default.nix b/pkgs/applications/misc/rtfm/default.nix
index 133bede81ae0..256ed98f9a8c 100644
--- a/pkgs/applications/misc/rtfm/default.nix
+++ b/pkgs/applications/misc/rtfm/default.nix
@@ -84,6 +84,7 @@ crystal.buildCrystalPackage rec {
     description = "Dash/docset reader with built in documentation for Crystal and GTK APIs";
     homepage = "https://github.com/hugopl/rtfm/";
     license = licenses.mit;
+    mainProgram = "rtfm";
     maintainers = with maintainers; [ sund3RRR ];
   };
 }