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 georgekhananaev/claude-skills-vault --skill better-authgit clone --depth 1 https://github.com/georgekhananaev/claude-skills-vaultWrote 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/georgekhananaev/claude-skills-vault/better-auth)<a href="https://agentmods.dev/skills/georgekhananaev/claude-skills-vault/better-auth"><img src="https://agentmods.dev/badge/skills/georgekhananaev/claude-skills-vault/better-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.
<a href="https://agentmods.dev/skills/georgekhananaev/claude-skills-vault/better-auth"><img src="https://agentmods.dev/badge/skills/georgekhananaev/claude-skills-vault/better-auth.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 | $0.00062 | $0.00391 |
| Opus 5 | $0.00031 | $0.00196 |
| Sonnet 5 | $0.00012 | $0.00078 |
| Haiku 4.5 | $0.00006 | $0.00039 |
Grade A, and why
better-auth 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 12d 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.
What it actually says
Better Auth Skills
Complete authentication setup and integration guide using Better Auth for TypeScript/JavaScript applications.
Available Sub-Skills
| Skill | File | Use When |
|---|---|---|
| Best Practices | best-practices-SKILL.md | Configuring Better Auth, database adapters, sessions, plugins, security |
| Create Auth | create-auth-SKILL.md | Scaffolding auth from scratch, adding login/signup to a project |
Quick Reference
Setup
npm install better-auth- Set
BETTER_AUTH_SECRETandBETTER_AUTH_URLenv vars - Create
auth.tswith database + config - Create route handler for your framework
- Run
npx @better-auth/cli@latest migrate
Supported Frameworks
Next.js (App/Pages Router), SvelteKit, Nuxt, Astro, Express, Hono, SolidStart
Supported Databases
PostgreSQL, MySQL, SQLite, MongoDB (via Prisma, Drizzle, or direct drivers)
Key Plugins
twoFactor, organization, passkey, magicLink, emailOtp, username, admin, apiKey, bearer, jwt, sso
Source
From better-auth/skills.
What ships with it
2 files 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.
- 12d ago First seen · 42 lines · 62 tokens per session scan A d0318f89874d
better-auth is a skill published in the GitHub repository georgekhananaev/claude-skills-vault (28 stars, last pushed 1mo ago), licensed MIT. It adds 62 tokens to every session and 391 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.
Other skills, from other repositories
nestjs-expert
Creates and configures NestJS modules, controllers, services, DTOs, guards, and interceptors for enterprise-grade TypeScript backend applications. Use when building NestJS REST APIs or GraphQL services, implementing dependency injection, scaffolding modular architecture, adding JWT/Passport authentication, integrating…
fastify-typescript
This skill should be used when using TypeScript with Fastify, configuring type providers, using @fastify/type-provider-typebox, using @fastify/type-provider-json-schema-to-ts, typing Fastify plugins, declaration merging for decorators, typing route handlers, FastifyInstance generics, FastifyRequest generics…
nestjs-expert
Provides NestJS patterns for modules, controllers, providers, guards, interceptors, and microservices. Use when working with NestJS TypeScript files (.module.ts, .controller.ts, .service.ts) or when the user mentions NestJS, Nest.js, or NestJS modules.
scraperapi-nodejs-sdk
Best-practices reference for the ScraperAPI Node.js / JavaScript SDK (scraperapi-sdk npm package). Consult whenever the user is writing, debugging, or reviewing JavaScript or TypeScript code that calls ScraperAPI. Use when user asks: "scrape a website with Node.js and ScraperAPI", "ScraperAPI JavaScript example", "how…
javascript-code
JavaScript/TypeScript development, paradigms, and runtime environments.
050101-elysia-framework
Elysia API framework patterns — plugin pipeline, controller conventions, auto-routing, auth macro, TypeBox models, and multi-tier API keys.