How to invite a user to a private github repo within an organisation using the command line - github

Question

I am trying to add users to a private Github repo within an organisation. Starting from this post, I've simply changed the API endpoint to cope with organizations (as explained here), and I end up with the following command:
gh api orgs/MY_ORG/repos/MY_USER_NAME/MY_REPO/collaborators/COLLABORATOR_USER_NAME -f '{"permission":"maintain"}';
This command systematically returns a 404 error (note that I also get a 404 when I just try to check if a user has access to a repo, i.e. the GET version of the above command).
I also need to mention that this doesn't seem to be a trivial gh auth login issue since a command like gh repo create MY_ORG/MY_REPO works fine.
Here is also some technical details:
os: macosx 10.15.16
git: 2.24.3
gh: 1.1.0

Answer 1

I take the initiative to answer my own question here since after some investigations (thanks to mislav for his help) and trials and errors, I ve found the proper way to add collaborators to a GitHub repo within an organization with the CLI. I think it is worth posting it, hopefully this will help others.
Invite an outside collaborator to a repo within an organization
gh api -X PUT repos/:org/:repo/collaborators/:username -f permission=:perm
the -X PUT specifies that the request is a PUT and not a GET (default request). The repo's identifier is specified by :org/:repo (note that if the repo is not under an organization, the identifier will be :owner/:repo). The :perm argument indicates the type of access, the default value is push (see here)
So assume I want to provide admin access to jonsnow to the repo winterfell under the organization got, I will use the following command
gh api -X PUT repos/got/winterfell/collaborators/jonsnow -f permission=admin
Note that if you send an invite for the repo directly, the user will appear as an outside collaborator (not as an organization member)
Add a member to the organization and invite him to a repo
You just need to include the user as a member to the organisation beforehand with
gh api -X PUT /orgs/:org/memberships/:username -f role=:role
and then you can provide him access to a specific repo with the same command as above, i.e.
gh api -X PUT repos/:org/:repo/collaborators/:username -f permission=:perm
Note that the value for the various :role can be found here

Answer 2

You can set organization membership for a user
put /orgs/{org}/memberships/{username}
You can add a collaborator to a repo
put /repos/{owner}/{repo}/collaborators/{username}
But I don't think you can combine the two (add a collaborator to an org repo)
That is because that collaborator need to be a member of the organisation first (so receive and accept the invitation), before being added to a repository.