create-auth-skill

A guide for adding Better Auth, a TypeScript and JavaScript authentication library, to an application. It covers detecting the app's framework, database, package manager, and existing login system before implementation.

In plain words
What is it for?
Use it to add login and sign-up, configure database adapters, connect OAuth providers such as Google or GitHub, set up server routes, and create authentication pages.
Why use it?
It helps fit authentication into the project's existing structure instead of guessing which framework, database, or package setup it uses. It also organizes the planning questions needed before changing the code.

Skill for Claude CodeCodex

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.

agentmods
npx agentmods add skills/pleaseai/claude-code-plugins/create-auth-skill
Any agent
npx skills add pleaseai/claude-code-plugins --skill create-auth-skill
Clone the repo
git clone --depth 1 https://github.com/pleaseai/claude-code-plugins

Made for: Claude Code, Codex.

Per session 66 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,045 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00066 $0.03045
Opus 5 $0.00033 $0.01522
Sonnet 5 $0.00013 $0.00609
Haiku 4.5 $0.00007 $0.00304

Measured 2d ago against content hash 5f21170914d4, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

create-auth-skill 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 2d 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.

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.

plugins/better-auth/.agents/skills/create-auth-skill/SKILL.md · 322 lines

How it starts

The opening of the file, as written. The whole thing — 322 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Create Auth Skill

Guide for adding authentication to TypeScript/JavaScript applications using Better Auth.

For code examples and syntax, see better-auth.com/docs.


Phase 1: Planning (REQUIRED before implementation)

Before writing any code, gather requirements by scanning the project and asking the user structured questions. This ensures the implementation matches their needs.

Step 1: Scan the project

Analyze the codebase to auto-detect:

  • Framework — Look for next.config, svelte.config, nuxt.config, astro.config, vite.config, or Express/Hono entry files.
  • Database/ORM — Look for prisma/schema.prisma, drizzle.config, package.json deps (pg, mysql2, better-sqlite3, mongoose, mongodb).
  • Existing auth — Look for existing auth libraries (next-auth, lucia, clerk, supabase/auth, firebase/auth) in package.json or imports.
  • Package manager — Check for pnpm-lock.yaml, yarn.lock, bun.lockb, or package-lock.json.

Use what you find to pre-fill defaults and skip questions you can already answer.

Step 2: Ask planning questions

Use the AskQuestion tool to ask the user all applicable questions in a single call. Skip any question you already have a confident answer for from the scan. Group them under a title like "Auth Setup Planning".

Questions to ask:

  1. Project type (skip if detected)

    • Prompt: "What type of project is this?"
    • Options: New project from scratch | Adding auth to existing project | Migrating from another auth library
  2. Framework (skip if detected)

    • Prompt: "Which framework are you using?"
    • Options: Next.js (App Router) | Next.js (Pages Router) | SvelteKit | Nuxt | Astro | Express | Hono | SolidStart | Other
  3. Database & ORM (skip if detected)

    • Prompt: "Which database setup will you use?"
    • Options: PostgreSQL (Prisma) | PostgreSQL (Drizzle) | PostgreSQL (pg driver) | MySQL (Prisma) | MySQL (Drizzle) | MySQL (mysql2 driver) | SQLite (Prisma) | SQLite (Drizzle) | SQLite (better-sqlite3 driver) | MongoDB (Mongoose) | MongoDB (native driver)

Read the full file on GitHub · 322 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. 2d ago First seen · 322 lines · 66 tokens per session scan A 5f21170914d4

Subscribe to this mod's changes

create-auth-skill is a skill published in the GitHub repository pleaseai/claude-code-plugins (13 stars, last pushed 7d ago), licensed MIT. It adds 66 tokens to every session and 3,045 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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