diff --git a/pkgs/development/python-modules/alembic/default.nix b/pkgs/development/python-modules/alembic/default.nix
index c1bb0f1d3c7d..36a6bb79bc27 100644
--- a/pkgs/development/python-modules/alembic/default.nix
+++ b/pkgs/development/python-modules/alembic/default.nix
@@ -47,5 +47,6 @@ buildPythonPackage rec {
     description = "A database migration tool for SQLAlchemy";
     license = licenses.mit;
     maintainers = with maintainers; [ ];
+    mainProgram = "alembic";
   };
 }
diff --git a/pkgs/development/python-modules/gunicorn/default.nix b/pkgs/development/python-modules/gunicorn/default.nix
index 23bfaae0d2bd..9a425be27878 100644
--- a/pkgs/development/python-modules/gunicorn/default.nix
+++ b/pkgs/development/python-modules/gunicorn/default.nix
@@ -43,5 +43,6 @@ buildPythonPackage rec {
     description = "gunicorn 'Green Unicorn' is a WSGI HTTP Server for UNIX, fast clients and sleepy applications";
     license = licenses.mit;
     maintainers = with maintainers; [ ];
+    mainProgram = "gunicorn";
   };
 }
diff --git a/pkgs/tools/text/chroma/default.nix b/pkgs/tools/text/chroma/default.nix
index af5241de7a05..2b59831529db 100644
--- a/pkgs/tools/text/chroma/default.nix
+++ b/pkgs/tools/text/chroma/default.nix
@@ -33,5 +33,6 @@ buildGoModule rec {
     description = "A general purpose syntax highlighter in pure Go";
     license = licenses.mit;
     maintainers = [ maintainers.sternenseemann ];
+    mainProgram = "chroma";
   };
 }