---

name: authentication-patterns description: | Authentication patterns for external services: API keys, OAuth, token management, verification.

Triggers: authentication, API keys, OAuth, token management, credentials Use when: integrating external services or implementing authentication flows category: infrastructure tags: [authentication, api-keys, oauth, tokens, security] dependencies: [error-patterns] provides: infrastructure: [authentication, credential-management, auth-verification] patterns: [api-key-auth, oauth-flow, token-refresh] usage_patterns:

• service-authentication
• credential-verification
• token-management complexity: beginner estimated_tokens: 400 progressive_loading: true modules:
• modules/auth-methods.md
• modules/verification-patterns.md

---

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

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}")

Smoke Test

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

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

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()
    )

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]

Integration Pattern

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

Detailed Resources

• Auth Methods: See modules/auth-methods.md for method details
• Verification: See modules/verification-patterns.md for testing patterns

Exit Criteria

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