The gh CLI likely defaults to using github.com as the host when interacting with GitHub.

SSH aliases in ~/.ssh/config are respected by Git itself, but the CLI may not map them correctly when creating remotes or resolving repository URLs.

I don't think gh repo create has a flag to make the generated remote URL use an SSH config alias like github.com-personal123.

gh's git settings only expose the protocol choice (https vs ssh), not an SSH host-alias selector. So when it adds the remote, it uses the normal GitHub SSH host form:

git@github.com:OWNER/REPO.git

not:

git@github.com-personal123:OWNER/REPO.git

So the practical workaround is:

1. let gh repo create create the repo and add the remote
2. rewrite the remote yourself afterward, e.g.

git remote set-url origin git@github.com-personal123:personal123/sample-repo.git

So my read is: SSH config aliases are respected by Git, but gh repo create does not currently provide a first-class way to emit remotes using those aliases.

I checked the gh code path for this and it looks like SSH host aliases are not a first-class option in gh repo create today. The relevant part of repo create takes the configured git protocol (https vs ssh) and then builds the remote with ghrepo.FormatRemoteURL(repo, protocol). In other words, it is formatting a normal GitHub remote URL from the repo + protocol, not consulting ~/.ssh/config for a custom host alias when it writes the remote.

So the current behavior makes sense:

• gh can create the repository on GitHub fine
• it adds a normal SSH remote like git@github.com:OWNER/REPO.git
• Git itself would respect github.com-personal123, but gh repo create is not emitting that alias in the generated remote URL

So the practical workaround is still to rewrite the remote after creation:

git remote set-url origin git@github.com-personal123:personal123/sample-repo.git

So my read is: supported protocol selection, yes; SSH config host-alias selection during remote creation, no.