I want to create a calendar based automation that changes the label on cards.

[Cam]

My workflow currently has a "Today's Tasks" and a "Tomorrow's Tasks" Label's I use to identify what needs to be done, I'd like all the "Tomorrow's Tasks" cards to automatically drop that label and apply the  "Today's Tasks" label at 4 AM every night, is this possible? I've tried making both a board button and a calendar rule, but options for changing labels does not exist in these automation areas.

[Loic]

Same issue here... every evening I label all the cards I want to act on the next day with the label "To do tomorrow", and every morning I manually change the label "To do tomorrow" to "To do today" on all relevant cards. I'd like to automate that with a board button.

@Cody Curryyour solution doesn't work for me because I already use lists to structure my different projects. I could reverse everything (identify projects with labels, and time frames with lists) however I now have a huge number of cards as I have been intensely working with Trello for some years.

There's no plan from the Trello team to develop a feature to act on labels with board buttons? I'm pretty sure there are other useful use cases...

[Cody Curry]

I did a bit of testing, and I'm afraid there isn't an easy way to do this with labels, but I do have a workaround I could suggest if you're open to changing that workflow a little bit.

What I like to do is have today and tomorrow's tasks represent by a list, rather than a label. If you do that, then there's a Butler action you could use to move all cards from the "Tomorrow's tasks" to "Today's tasks" at 4am:

every day at 4:00 am, move each card in list "Tomorrow's tasks" to list "Today's tasks"

The only way I can think of to do it with Labels would be with two rules. One that moves cards to a "trigger" list, and another that performs an action when a card is moved into that "trigger" list. Something like this:

1. every day at 4:00 am, move each card with "tomorrow's tasks" label to list "trigger list"
2. when a card is added to list "trigger list", remove "tomorrow's tasks" label, add "today's task" label