zsh completions works weird on my todo list

[Shmerlard]

hey, so I'm writing my todo program in cpp, and i accidentally pressed TAB after writing todo and my kitty terminal just crashed,
after some tinkering i've found that zsh uses --format in order to print the suggestions so naively i've tried this:

int main(int argc, char* argv[])
{
    if ((argc > 3) && (string(argv[3]) == "--format")){
        cout << "-h: show this menu";
        cout << "-a: add to task list";
        cout << "-r: remove task with index <idx>" << std::endl;
        cout << "-t: toggle check/uncheck index <idx>" << std::endl;
        cout << "-c: clear, remove all marked task (WIP)" << std::endl;
        cout << "-f: toggle favorite index <idx>" << std::endl;
        cout << "-e: edit task with index <idx>" << std::endl;
        cout << "-j: export to json (backup) (WIP)" << std::endl;
        cout << "-u: undo (WIP)" << std::endl;
        return 0;
    }

    cout << "Welcome to my todo list program!\n";
    ...

but i've got some weird output like

❯ todo -u
--add               -a  -- add item                                                                                                                                                         
--all               -A  -- show all items                                                                                                                                                   
--backup                -- backup database                                                                                                                                                  
--colour                -- item color                                                                                                                                                       
XXXXXX                                                                                                                                                                                                                                                        
--version               -- display version                                                                                                                                                  
-c  --  clear, remove all marked task (WIP)
-e  --  edit task with index <idx>
-f  --  toggle favorite index <idx>
-h  --  show this menu-a: add to task list-r: remove task with index <idx>
-j  --  export to json (backup) (WIP)
-t  --  toggle check/uncheck index <idx>
-u  --  undo (WIP)

the XXX is to save space i had like 30 more lines there.

or when i change to

    if ((argc > 3) && (string(argv[3]) == "--format")) {
        cout << "-h        : show this menu\n";
        cout << "-a <tasks>: add <tasks> to task list\n";
        cout << "-r <array>: remove task with index <idx>\n";
        cout << "-t <array>: toggle check/uncheck index <idx>\n";
        cout << "-c        : clear, remove all marked task (WIP)\n";
        cout << "-f <array>: toggle favorite index <idx>\n";
        cout << "-e <idx>  : edit task with index <idx>\n";
        cout << "-j <path> : export to json (backup) (WIP)\n";
        cout << "-u        : undo (WIP)\n";
        return 0;
    }

i get

❯ todo
-h.-a<tasks>              --  add <tasks> to task list
-h.-f<array>.-e<idx>      --  edit task with index <idx>
-h.-f<array>.-j<path>     --  export to json (backup) (WIP)
-h.-f<array>.-j<path>.-u  --  undo (WIP)
-h.-f<array>              --  toggle favorite index <idx>
-h.-r<array>              --  remove task with index <idx>
.-h                       --  show this menu
-h.-t<array>.-c           --  clear, remove all marked task (WIP)
-h.-t<array>              --  toggle check/uncheck index <idx>

so my questions are
is why is that?
is adding some output like i did is a good way to support zsh-autocomplete?
where did the other commands of todo like --backup --all came from?

thanks!