Is there a way to auto refill the inventory of the baritone bot? I want to build a 161x161 dirt layer for a big farm. Or what's the easiest way to do this?

It does not refill it's inventory automatically.
If you are able to do it, you can use baritones API to add that feature yourself, otherwise you will simply need to manually refill your inventory (or let someone else do the work 😄).
For the dirt layer:

1. select the area
2. use sel fill dirt

Ok thanks, I might have an idea. I have some experience with a other mod to make scripts (macro mod) and i could let that take the dirt and then let baritone build again?

As long as it runs #pause and #resume, sure

With java it is probably easier because you can hook into baritone directly bot a macro mod should also work

I don't really have any experience with java.

Then use your macro mod
As @Dominikaaaa said you can #pause and #resume if you don't need baritone to get the blocks.
If you need it (e.g. to go to a chest) then use #cancel to stop, #goto to go to your chest and #sel fill to restart builing.

Also check out #1706. I don't know if it is usable but if it is, it is everything you need (assuming you have shulkerboxes)

Thanks!

Don't have shulker boxes tho, im trying this on hypixel skyblock (1.8)