I am facing with this error when making arc diff --preview command :

ERROR 8: Undefined index: Repository UUID at [...]
[...]
SKIP STAGING Unable to determine repository for this change.

Possible similar issues:
It seems is similar to this task: T10460, but I cannot make the error disappear.

Reproduction Steps:
I want to avoid the file .arcconfig, so I am setting the properties directly this way:

arc set-config default <URI>

cat ~/.arcrc

{
  "config": {
    "default": "<URI>"
  },
  "hosts": {
    "http:<URI>/api": {
      "token": "<token>"
    }
  }
}

It seems I do not include the callsign of a repository. I tried to set properties like these ones without success:

arc set-config repository.callsign <REPO CALLSIGN PREVIOUSLY DEFINED>

or

arc set-config callsign <REPO CALLSIGN PREVIOUSLY DEFINED>

The question if there is a way to do this and have this configuration in ~/.arcrc file

Versions
arcanist 20ad47f2733135603d57b57be3e13422397e8071 (Fri, May 5)
phutil d02cc05931b02c684d4c729510090591ca45f951 (Sat, Apr 29)

Thanks in advance.
Juan