/github-auth

name: github-auth
description: Set up GitHub authentication for the agent using git (universally available) or the gh CLI. Covers HTTPS tokens, SSH keys, credential helpers, and gh auth — with a detection flow to pick the right method automatically.
version: 1.1.0
author: Zorro Agent
license: MIT
metadata:
  zorro:
    tags: [GitHub, Authentication, Git, gh-cli, SSH, Setup]
    related_skills: [github-pr-workflow, github-code-review, github-issues, github-repo-management]

GitHub Authentication Setup

This skill sets up authentication so the agent can work with GitHub repositories, PRs, issues, and CI. It covers two paths:

• **`git` (always available)** — uses HTTPS personal access tokens or SSH keys
• **`gh` CLI (if installed)** — richer GitHub API access with a simpler auth flow

Detection Flow

When a user asks you to work with GitHub, run this check first:

# Check what's available
git --version
gh --version 2>/dev/null || echo "gh not installed"

# Check if already authenticated
gh auth status 2>/dev/null || echo "gh not authenticated"
git config --global credential.helper 2>/dev/null || echo "no git credential helper"

**Decision tree:** 1. If `gh auth status` shows authenticated → you're good, use `gh` for everything 2. If `gh` is installed but not authenticated → use "gh auth" method below 3. If `gh` is not installed → use "git-only" method below (no sudo needed)

---

Method 1: Git-Only Authentication (No gh, No sudo)

This works on any machine with `git` installed. No root access needed.

Option A: HTTPS with Personal Access Token (Recommended)

This is the most portable method — works everywhere, no SSH config needed.

**Step 1: Create a personal access token**

Tell the user to go to: **https://github.com/settings/tokens**

• Click "Generate new token (classic)"
• Give it a name like "zorro-agent"
• Select scopes:
• `repo` (full repository access — read, write, push, PRs)
• `workflow` (trigger and manage GitHub Actions)
• `read:org` (if working with organization repos)
• Set expiration (90 days is a good default)
• Copy the token — it won't be shown again

**Step 2: Configure git to store the token**

# Set up the credential helper to cache credentials
# "store" saves to ~/.git-credentials in plaintext (simple, persistent)
git config --global credential.helper store

# Now do a test operation that triggers auth — git will prompt for credentials
# Username: <their-github-username>
# Password: <paste the personal access token, NOT their GitHub password>
git ls-remote https://github.com/<their-username>/<any-repo>.git

After entering credentials once, they're saved and reused for all future operations.

**Alternative: cache helper (credentials expire from memory)**

# Cache in memory for 8 hours (28800 seconds) instead of saving to disk
git config --global credential.helper 'cache --timeout=28800'

**Alternative: set the token directly in the remote URL (per-repo)**

# Embed token in the remote URL (avoids credential prompts entirely)
git remote set-url origin https://<username>:<token>@github.com/<owner>/<repo>.git

**Step 3: Configure git identity**

# Required for commits — set name and email
git config --global user.name "Their Name"
git config --global user.email "their-email@example.com"

**Step 4: Verify**

# Test push access (this should work without any prompts now)
git ls-remote https://github.com/<their-username>/<any-repo>.git

# Verify identity
git config --global user.name
git config --global user.email

Option B: SSH Key Authentication

Good for users who prefer SSH or already have keys set up.

**Step 1: Check for existing SSH keys**

ls -la ~/.ssh/id_*.pub 2>/dev/null || echo "No SSH keys found"

**Step 2: Generate a key if needed**

# Generate an ed25519 key (modern, secure, fast)
ssh-keygen -t ed25519 -C "their-email@example.com" -f ~/.ssh/id_ed25519 -N ""

# Display the public key for them to add to GitHub
cat ~/.ssh/id_ed25519.pub

Tell the user to add the public key at: **https://github.com/settings/keys**

• Click "New SSH key"
• Paste the public key content
• Give it a title like "zorro-agent-<machine-name>"

**Step 3: Test the connection**

ssh -T git@github.com
# Expected: "Hi <username>! You've successfully authenticated..."

**Step 4: Configure git to use SSH for GitHub**

# Rewrite HTTPS GitHub URLs to SSH automatically
git config --global url."git@github.com:".insteadOf "https://github.com/"

**Step 5: Configure git identity**

git config --global user.name "Their Name"
git config --global user.email "their-email@example.com"

---

Method 2: gh CLI Authentication

If `gh` is installed, it handles both API access and git credentials in one step.

Interactive Browser Login (Desktop)

gh auth login
# Select: GitHub.com
# Select: HTTPS
# Authenticate via browser

Token-Based Login (Headless / SSH Servers)

echo "<THEIR_TOKEN>" | gh auth login --with-token

# Set up git credentials through gh
gh auth setup-git

Verify

gh auth status

---

Using the GitHub API Without gh

When `gh` is not available, you can still access the full GitHub API using `curl` with a personal access token. This is how the other GitHub skills implement their fallbacks.

Setting the Token for API Calls

# Option 1: Export as env var (preferred — keeps it out of commands)
export GITHUB_TOKEN="<token>"

# Then use in curl calls:
curl -s -H "Authorization: token $GITHUB_TOKEN" \
  https://api.github.com/user

Extracting the Token from Git Credentials

If git credentials are already configured (via credential.helper store), the token can be extracted:

# Read from git credential store
grep "github.com" ~/.git-credentials 2>/dev/null | head -1 | sed 's|https://[^:]*:\([^@]*\)@.*|\1|'

Helper: Detect Auth Method

Use this pattern at the st