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 "hermes-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 "[email protected]"

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 "[email protected]" -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 "hermes-agent-<machine-name>"

Step 3: Test the connection

ssh -T [email protected]
# 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."[email protected]:".insteadOf "https://github.com/"

Step 5: Configure git identity

git config --global user.name "Their Name"
git config --global user.email "[email protected]"

Method 2: gh CLI Authentication

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

Interactive Browser Login (Desktop)

PITFALL (agent-driven sessions on Windows): when driving gh auth login through a pty background process, answer prompts with process(submit) — never process(write) with a bare \n. Enter on a Windows PTY (ConPTY/pywinpty) is a carriage return; a lone \n is not delivered as a line terminator, so gh's "Press Enter to open the browser" prompt (a blocking line read) silently never returns and the login hangs. Also note the browser may not open on the user's desktop from a background session — if they report that, fall back to the device flow below.

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

Manual OAuth Device Flow (no TTY needed — PROVEN)

Fallback when interactive login is impractical (agent-driven sessions, no browser launch, headless). Uses gh's public OAuth client id; the user just enters a code at github.com/login/device. Scopes: repo,read:org,gist is the documented minimum for gh auth login --with-token; append ,workflow only if you need to push workflow files.

# 1. Request a device code (gh's official client_id)
RESP=$(curl -s -X POST -H "Accept: application/json" \
  -d "client_id=178c6fc778ccc68e1d6a&scope=repo,read:org,gist" \
  https://github.com/login/device/code)
DEVICE_CODE=$(echo "$RESP" | sed 's/.*"device_code":"\([^"]*\)".*/\1/')
USER_CODE=$(echo "$RESP" | sed 's/.*"user_code":"\([^"]*\)".*/\1/')
INTERVAL=$(echo "$RESP" | sed 's/.*"interval":\([0-9]*\).*/\1/'); INTERVAL=${INTERVAL:-5}
echo "Tell the user: go to https://github.com/login/device and enter code: $USER_CODE"

# 2. Poll for the token (respect interval; +5s on slow_down; ~15 min expiry).
#    Run this loop as a background process and show the user the code first.
while true; do
  sleep "$INTERVAL"
  POLL=$(curl -s -X POST -H "Accept: application/json" \
    -d "client_id=178c6fc778ccc68e1d6a&device_code=${DEVICE_CODE}&grant_type=urn:ietf:params:oauth:grant-type:device_code" \
    https://github.com/login/oauth/access_token)
  case "$POLL" in
    *access_token*)
      # Never echo the token; pipe it straight into gh.
      # timeout guards the headless-keyring hang (see pitfall below) —
      # on exit 124, fall back to writing ~/.config/gh/hosts.yml directly.
      echo "$POLL" | sed 's/.*"access_token":"\([^"]*\)".*/\1/' | timeout 20 gh auth login --with-token \
        || { echo "WITH_TOKEN_HUNG_OR_FAILED — use the hosts.yml fallback below"; exit 1; }
      gh auth setup-git
      gh auth status
      echo "LOGIN_COMPLETE"; break ;;
    *authorization_pending*) ;;                      # keep polling
    *slow_down*) INTERVAL=$((INTERVAL + 5)) ;;       # back off per GitHub docs
    *expired_token*) echo "CODE_EXPIRED — restart the flow"; exit 1 ;;
    *access_denied*) echo "USER_DENIED"; exit 1 ;;
    *) echo "UNEXPECTED: $POLL"; exit 1 ;;
  esac
done

Note: on Windows winget installs, gh lands at /c/Program Files/GitHub CLI — add it to PATH in the same shell: export PATH="$PATH:/c/Program Files/GitHub CLI".

PITFALL (headless Linux): gh auth login --with-token can hang forever. On keyring-less/headless boxes (VPS, containers, no dbus session), gh's credential storage may block indefinitely waiting on a secret-service keyring — even with --insecure-storage, and with no output. If the command doesn't return within ~20s (wrap it in timeout 20 … to detect this), skip gh's login machinery and write the credential store directly:

bashCopy

# $TOKEN = the access token from the device flow above (never echo it)
mkdir -p ~/.config/gh
LOGIN=$(curl -s -H "Authorization: token $TOKEN" https://api.github.com/user \
  | sed 's/.*"login": *"\([^"]*\)".*/\1/')
printf 'github.com:\n    users:\n        %s:\n            oauth_token: %s\n    git_protocol: https\n    oauth_token: %s\n    user: %s\n' \
  "$LOGIN" "$TOKEN" "$TOKEN" "$LOGIN" > ~/.config/gh/hosts.yml
chmod 600 ~/.config/gh/hosts.yml
gh auth status          # reads hosts.yml directly — verifies without the keyring
gh auth setup-git       # wires the git credential helper (does not hang)

gh auth status and setup-git read the file store without touching the keyring, so they work immediately. Proven on a headless x86_64 VPS (gh 2.97.0, Aug 2026) after --with-token hung twice.

Token-Based Login (Headless / SSH Servers)

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

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

If --with-token hangs here, use the hosts.yml fallback from the pitfall above.

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
uv run python "${HERMES_HOME:-$HOME/.hermes}/skills/github/github-auth/scripts/git-credential-token.py"

Helper: Detect Auth Method

Use this pattern at the start of any GitHub workflow:

# Try gh first, fall back to git + curl
if command -v gh &>/dev/null && gh auth status &>/dev/null; then
  echo "AUTH_METHOD=gh"
elif [ -n "$GITHUB_TOKEN" ]; then
  echo "AUTH_METHOD=curl"
elif _hermes_env="${HERMES_HOME:-$HOME/.hermes}/.env"; [ -f "$_hermes_env" ] && grep -q "^GITHUB_TOKEN=" "$_hermes_env"; then
  export GITHUB_TOKEN=$(grep "^GITHUB_TOKEN=" "$_hermes_env" | head -1 | cut -d= -f2 | tr -d '\n\r')
  echo "AUTH_METHOD=curl"
elif grep -q "github.com" ~/.git-credentials 2>/dev/null; then
  export GITHUB_TOKEN=$(uv run python "${HERMES_HOME:-$HOME/.hermes}/skills/github/github-auth/scripts/git-credential-token.py")
  echo "AUTH_METHOD=curl"
else
  echo "AUTH_METHOD=none"
  echo "Need to set up authentication first"
fi

Troubleshooting