GitHub Multi-Account SSH

Use this skill when the user works with multiple GitHub identities and any of these happen:

• gh repo create targets the wrong owner
• git push fails with Permission denied (publickey)
• the repository remote uses github.com but the machine is configured with SSH host aliases like dinghao.github.com
• gh is authenticated as one account while git or SSH is effectively using another

Goal

Make GitHub ownership, CLI auth, git author identity, and SSH transport line up cleanly.

Quick Workflow

1. Check current GitHub CLI identity.
2. Check current git remote.
3. Check current SSH auth path.
4. Decide whether to use github.com or a configured host alias.
5. Fix local repo config only, not global config, unless the user explicitly asks.

Step 1: Check CLI Identity

Run:

gh auth status
gh api user

If the active gh identity is wrong for the target owner, switch it:

gh auth switch -u <username>

Do this before gh repo create, gh repo view, or any owner-specific GitHub action.

Step 2: Check Git Remote

Run:

git remote -v

Look for one of these patterns:

• Standard host:

- [email protected]:<owner>/<repo>.git - https://github.com/<owner>/<repo>.git

• Alias host:

- [email protected]:<owner>/<repo>.git

If the machine is already configured with SSH aliases, prefer the alias host instead of generic github.com.

Step 3: Check SSH Setup

Run:

ls -la ~/.ssh
ssh-add -l
sed -n '1,220p' ~/.ssh/config

Interpretation:

• If ssh-add -l says The agent has no identities, agent-based auth is not active.
• If ~/.ssh/config defines Host alice.github.com with IdentityFile ~/.ssh/alice, then remotes for that identity should use [email protected]:<owner>/<repo>.git.
• If there is no Host github.com entry, generic [email protected] may fail even when alias-based SSH works.

Step 4: Test The Correct Host

Never assume the failing host and the working host are the same.

Test exactly what the remote should use:

ssh -T [email protected]
ssh -T [email protected]

Expected success output:

Hi <username>! You've successfully authenticated, but GitHub does not provide shell access.

Step 5: Fix The Remote

If the user already has an alias host configured, set the remote to match it:

git remote set-url origin [email protected]:<owner>/<repo>.git

If alias SSH is unavailable but gh works, HTTPS is a valid temporary fallback:

git remote set-url origin https://github.com/<owner>/<repo>.git

After any temporary HTTPS fallback used only for bootstrapping, switch back to the intended SSH remote if the user prefers SSH.

Step 6: Fix Commit Identity Safely

Check current git author identity:

git config --get user.name
git config --get user.email

If it does not match the intended owner, set repo-local config only:

git config user.name <username>
git config user.email <noreply-or-approved-email>

Do not change global git identity unless explicitly requested.

Common Failure Patterns

gh repo create says the active account cannot create a repo for the owner

Cause:

• gh is authenticated as the wrong account

Fix:

gh auth switch -u <owner>

git push over SSH fails but gh repo view works

Cause:

• GitHub CLI auth is fine, but SSH host/key selection is wrong

Fix:

• inspect ~/.ssh/config
• switch remote to the correct alias host
• test with ssh -T against that exact alias

First push works only over HTTPS

Cause:

• SSH path is misconfigured or unavailable in the current environment

Fix:

• use HTTPS only as a bootstrap fallback
• then restore the SSH remote once the correct alias host is verified

Preferred Outcome

For each repo, the following should be true:

• gh active account matches the intended GitHub owner
• repo-local git author identity matches the intended owner
• origin uses the correct SSH alias host for that owner
• ssh -T succeeds for that exact alias host

Example

If ~/.ssh/config contains:

Host alice.github.com
    Hostname ssh.github.com
    Port 443
    User git
    IdentitiesOnly yes
    IdentityFile ~/.ssh/alice

Then the correct remote form is:

git remote set-url origin [email protected]:alice/<repo>.git

And the correct auth test is:

ssh -T [email protected]