auth

auth is a skill for Claude Code, Codex from Benja-Pauls/SerpentStack. It costs 48 tokens per session (1,558 once invoked), scanned A, original, MIT.

A guide to the project's built-in login system, which uses passwords and JWT tokens, plus instructions for replacing it with providers such as Clerk, Auth0, or custom single sign-on.

In plain words
What is it for?
Use it when adding authentication to routes, changing authentication providers, investigating login problems, or working with the user data available to protected routes.
Why use it?
It explains how login, password storage, tokens, and protected routes fit together, reducing guesswork when adding or debugging access control.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it when adding authentication to routes, changing authentication providers, investigating login problems, or working with the user data available to protected routes.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/benja-pauls/serpentstack/auth
Install

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.

Any agent
npx skills add Benja-Pauls/SerpentStack --skill auth
Clone the repo
git clone --depth 1 https://github.com/Benja-Pauls/SerpentStack

Made for: Claude Code, Codex.

Wrote 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.

agentmods badge for auth

README.md
[![agentmods](https://agentmods.dev/badge/skills/benja-pauls/serpentstack/auth/github.svg)](https://agentmods.dev/skills/benja-pauls/serpentstack/auth)
Your own site
<a href="https://agentmods.dev/skills/benja-pauls/serpentstack/auth"><img src="https://agentmods.dev/badge/skills/benja-pauls/serpentstack/auth/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.

agentmods 80×15 button for auth

Your own site · 80×15
<a href="https://agentmods.dev/skills/benja-pauls/serpentstack/auth"><img src="https://agentmods.dev/badge/skills/benja-pauls/serpentstack/auth.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 48 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,558 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00048 $0.01558
Opus 5.5 $0.00019 $0.00623
Sonnet 5.5 $0.00010 $0.00312
Haiku 4.5 $0.00005 $0.00156

Measured 1mo ago against content hash a555887974cf, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

auth scanned grade A with 1 finding 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 1mo ago.

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.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

curl -X POST http://localhost:8000/api/v1/auth/register \
.skills/auth/SKILL.md · 186 lines

How it starts

The opening of the file, as written. The whole thing — 186 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Auth

SerpentStack ships with working local JWT authentication (register, login, token validation). This skill explains the auth architecture and how to swap providers.

How Auth Works (Built-in)

Architecture

POST /api/v1/auth/register  →  UserService.register()  →  bcrypt hash  →  DB  →  JWT
POST /api/v1/auth/login     →  UserService.authenticate()  →  verify hash  →  JWT
GET  /api/v1/auth/me        →  get_current_user dependency  →  decode JWT  →  UserResponse

Any protected route:
    @router.delete("/{id}")
    async def delete(user: UserInfo = Depends(get_current_user)):
        # user.user_id, user.email available here

Key Files

File Role
backend/app/routes/auth.py Auth routes + get_current_user dependency
backend/app/services/user.py Registration, authentication, password hashing
backend/app/models/user.py User SQLAlchemy model (email, hashed_password)
backend/app/schemas/user.py Request/response schemas (register, login, token)
backend/app/middleware/auth.py Optional global auth middleware (not enabled by default)

The UserInfo Contract

All protected routes receive a UserInfo object via dependency injection:

class UserInfo(BaseModel):
    user_id: str
    email: str | None = None
    name: str | None = None
    raw_claims: dict[str, Any] = {}

This is the interface between auth and the rest of the app. When swapping providers, keep this shape — every route that uses Depends(get_current_user) depends on it.

Protecting a Route

Add Depends(get_current_user) to any route that requires authentication:

from app.routes.auth import UserInfo, get_current_user

@router.post("")
async def create_thing(
    payload: ThingCreate,
    user: UserInfo = Depends(get_current_user),  # ← requires valid JWT
    db: AsyncSession = Depends(get_db),
    service: ThingService = Depends(get_thing_service),
) -> ThingResponse:
    thing = await service.create(payload, owner_id=user.user_id)
    await db.commit()
    return ThingResponse.model_validate(thing)

Read the full file on GitHub · 186 lines

Changes

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.

  1. 1mo ago First seen · 186 lines · 48 tokens per session scan A a555887974cf

Subscribe to this mod's changes

auth is a skill published in the GitHub repository Benja-Pauls/SerpentStack (2 stars, last pushed 6mo ago), licensed MIT. It adds 48 tokens to every session and 1,558 once invoked, about $0.0002 per session on Opus 5.5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

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