Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add frontal-labs/mcp-server --skill auth-implementation-patternsgit clone --depth 1 https://github.com/frontal-labs/mcp-serverWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/frontal-labs/mcp-server/auth-implementation-patterns)<a href="https://agentmods.dev/skills/frontal-labs/mcp-server/auth-implementation-patterns"><img src="https://agentmods.dev/badge/skills/frontal-labs/mcp-server/auth-implementation-patterns/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/frontal-labs/mcp-server/auth-implementation-patterns"><img src="https://agentmods.dev/badge/skills/frontal-labs/mcp-server/auth-implementation-patterns.svg" alt="Reviewed on agentmods" width="80" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00046 | $0.00594 |
| Opus 5.5 | $0.00018 | $0.00238 |
| Sonnet 5.5 | $0.00009 | $0.00119 |
| Haiku 4.5 | $0.00005 | $0.00059 |
Grade A, and why
auth-implementation-patterns scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured yesterday.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
This is a copy
100% identical to auth-implementation-patterns — 0 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.
How it starts
The opening of the file, as written. The whole thing — 84 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Authentication & Authorization Implementation Patterns
Build secure, scalable authentication and authorization systems using industry-standard patterns and modern best practices.
When to Use This Skill
- Implementing user authentication systems
- Securing REST or GraphQL APIs
- Adding OAuth2/social login
- Implementing role-based access control (RBAC)
- Designing session management
- Migrating authentication systems
- Debugging auth issues
- Implementing SSO or multi-tenancy
Core Concepts
1. Authentication vs Authorization
Authentication (AuthN): Who are you?
- Verifying identity (username/password, OAuth, biometrics)
- Issuing credentials (sessions, tokens)
- Managing login/logout
Authorization (AuthZ): What can you do?
- Permission checking
- Role-based access control (RBAC)
- Resource ownership validation
- Policy enforcement
2. Authentication Strategies
Session-Based:
- Server stores session state
- Session ID in cookie
- Traditional, simple, stateful
Token-Based (JWT):
- Stateless, self-contained
- Scales horizontally
- Can store claims
OAuth2/OpenID Connect:
- Delegate authentication
- Social login (Google, GitHub)
- Enterprise SSO
Detailed patterns and worked examples
Detailed pattern documentation lives in references/details.md. Read that file when the navigation tier above is insufficient.
Best Practices
- Never Store Plain Passwords: Always hash with bcrypt/argon2
- Use HTTPS: Encrypt data in transit
- Short-Lived Access Tokens: 15-30 minutes max
- Secure Cookies: httpOnly, secure, sameSite flags
- Validate All Input: Email format, password strength
- Rate Limit Auth Endpoints: Prevent brute force attacks
- Implement CSRF Protection: For session-based auth
- Rotate Secrets Regularly: JWT secrets, session secrets
- Log Security Events: Login attempts, failed auth
- Use MFA When Possible: Extra security layer
Common Pitfalls
- Weak Passwords: Enforce strong password policies
- JWT in localStorage: Vulnerable to XSS, use httpOnly cookies
- No Token Expiration: Tokens should expire
- Client-Side Auth Checks Only: Always validate server-side
- Insecure Password Reset: Use secure tokens with expiration
- No Rate Limiting: Vulnerable to brute force
- Trusting Client Data: Always validate on server
What ships with it
1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- yesterday First seen · 84 lines · 46 tokens per session scan A 1fc61d6074ac
auth-implementation-patterns is a skill published in the GitHub repository frontal-labs/mcp-server (1 stars, last pushed yesterday), licensed Apache-2.0. It adds 46 tokens to every session and 594 once invoked, about $0.0002 per session on Opus 5.5. A static security scan graded it A with 0 findings. It is 100% identical to auth-implementation-patterns, differing in 0 lines, and is treated as a copy.
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