> todo.sh --help gives only a summary of the internal commands
> todo.sh help gives the full help including [extensions]

Ah, that's interesting - and a little confusing (even though --help does
say 'See "help" for more details.').
Thanks for the clarification!

> there was a bug fix that prevented "todo.sh help" from making the usage
> calls to the addons; I think that bugfix got applied after the 2.3 release

It seems to work fine for me on v2.3 stable.

Aside: I have also adapted Philipe's edit command - mostly to make the
item argument optional:
http://github.com/FND/todo.txt-cli/blob/extensions/edit


-- F.