Table of Contents

• Overview
• When to Use
• Authentication Methods
• Quick Start
• Verify Authentication
• Smoke Test
• Standard Flow
• Step 1: Check Environment
• Step 2: Verify with Service
• Step 3: Handle Failures
• Integration Pattern
• Detailed Resources
• Exit Criteria

Authentication Patterns

Overview

Common authentication patterns for integrating with external services. Provides consistent approaches to credential management, verification, and error handling.

When To Use

• Integrating with external APIs
• Need credential verification
• Managing multiple auth methods
• Handling auth failures gracefully

When NOT To Use

• Project doesn't use the leyline infrastructure patterns
• Simple scripts without service architecture needs

Authentication Methods

Method	Best For	Environment Variable
API Key	Simple integrations	{SERVICE}_API_KEY
OAuth	User-authenticated	Browser-based flow
Token	Session-based	{SERVICE}_TOKEN
None	Public APIs	N/A

Quick Start

Verify Authentication

from leyline.auth import verify_auth, AuthMethod

# API Key verification
status = verify_auth(
    service="gemini",
    method=AuthMethod.API_KEY,
    env_var="GEMINI_API_KEY"
)

if not status.authenticated:
    print(f"Auth failed: {status.message}")
    print(f"Action: {status.suggested_action}")

Verification: Run the command with --help flag to verify availability.

Smoke Test

def verify_with_smoke_test(service: str) -> bool:
    """Verify auth with simple request."""
    result = execute_simple_request(service, "ping")
    return result.success

Verification: Run pytest -v to verify tests pass.

Standard Flow

Step 1: Check Environment

def check_credentials(service: str, env_var: str) -> bool:
    value = os.getenv(env_var)
    if not value:
        print(f"Missing {env_var}")
        return False
    return True

Verification: Run the command with --help flag to verify availability.

Step 2: Verify with Service

def verify_with_service(service: str) -> AuthStatus:
    result = subprocess.run(
        [service, "auth", "status"],
        capture_output=True
    )
    return AuthStatus(
        authenticated=(result.returncode == 0),
        message=result.stdout.decode()
    )

Verification: Run the command with --help flag to verify availability.

Step 3: Handle Failures

def handle_auth_failure(service: str, method: AuthMethod) -> str:
    actions = {
        AuthMethod.API_KEY: f"Set {service.upper()}_API_KEY environment variable",
        AuthMethod.OAUTH: f"Run '{service} auth login' for browser auth",
        AuthMethod.TOKEN: f"Refresh token with '{service} token refresh'"
    }
    return actions[method]

Verification: Run the command with --help flag to verify availability.

Integration Pattern

# In your skill's frontmatter
dependencies: [leyline:authentication-patterns]

Verification: Run the command with --help flag to verify availability.

Interactive Authentication (Shell)

For workflows requiring interactive authentication with token caching and session management:

# Source the interactive auth script
source plugins/leyline/scripts/interactive_auth.sh

# Ensure authentication before proceeding
ensure_auth github || exit 1
ensure_auth gitlab || exit 1
ensure_auth aws || exit 1

# Continue with authenticated operations
gh pr view 123
glab issue list
aws s3 ls

Features:

• ✅ Interactive OAuth flows for GitHub, GitLab, AWS, and more
• ✅ Token caching (5-minute TTL)
• ✅ Session persistence (24-hour TTL)
• ✅ CI/CD compatible (auto-detects non-interactive environments)
• ✅ Multi-service support

See modules/interactive-auth.md for complete documentation.

Detailed Resources

• Auth Methods: See modules/auth-methods.md for method details
• Verification: See modules/verification-patterns.md for testing patterns
• Interactive: See modules/interactive-auth.md for shell-based auth flows

Exit Criteria

• Credentials verified or clear failure message
• Suggested action for auth failures
• Smoke test confirms working auth

Troubleshooting

Common Issues

Command not found Ensure all dependencies are installed and in PATH

Permission errors Check file permissions and run with appropriate privileges

Unexpected behavior Enable verbose logging with --verbose flag