better-auth

better-auth is a skill for Claude Code from secondsky/claude-skills. It costs 53 tokens per session (7,744 once invoked), scanned A, original, MIT.

A TypeScript authentication framework for adding sign-in and access control to applications, including projects using Cloudflare D1, Next.js, Nuxt, and other frameworks. It supports options such as OAuth, two-factor authentication, and role-based access control.

In plain words
What is it for?
Use it when adding authentication, connecting Better Auth to D1 with native support or an ORM, upgrading versions, or implementing OAuth, two-factor authentication, or role-based permissions.
Why use it?
It gives an application a way to handle users and authentication across several web frameworks. It also documents setup details such as database adapters and the ESM module format.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the better-auth plugin — 1 skill, 4 commands, 1 agent shipped together

not rated 235repo +4 3d ago A scan Socket: passSnyk: passSkillSpector: warn 53 tokens original MIT

Good fit Use it when adding authentication, connecting Better Auth to D1 with native support or an ORM, upgrading versions, or implementing OAuth, two-factor authentication, or role-based permissions.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/secondsky/claude-skills/better-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 secondsky/claude-skills --skill better-auth
Clone the repo
git clone --depth 1 https://github.com/secondsky/claude-skills

Made for: Claude Code.

Or install better-auth, the plugin that ships this one along with the rest of its 1 skill, 4 commands, 1 agent.

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 better-auth

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

agentmods 80×15 button for better-auth

Your own site · 80×15
<a href="https://agentmods.dev/skills/secondsky/claude-skills/better-auth"><img src="https://agentmods.dev/badge/skills/secondsky/claude-skills/better-auth.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 53 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 7,744 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • Socket pass 15 Sept 2026
  • Snyk pass 14 Sept 2026
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 8 findings, up to medium

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

  • medium MCP Rug Pull · line 190
    npx commands without a version suffix (e.g. @1.0.0) create a rug-pull risk if the upstream server is compromised and publishes a malicious update.
    Fix: Pin the version: npx @scope/[email protected]
  • medium MCP Rug Pull · line 230
    npx commands without a version suffix (e.g. @1.0.0) create a rug-pull risk if the upstream server is compromised and publishes a malicious update.
    Fix: Pin the version: npx @scope/[email protected]
  • medium MCP Rug Pull · line 270
    npx commands without a version suffix (e.g. @1.0.0) create a rug-pull risk if the upstream server is compromised and publishes a malicious update.
    Fix: Pin the version: npx @scope/[email protected]
  • medium MCP Rug Pull · line 271
    npx commands without a version suffix (e.g. @1.0.0) create a rug-pull risk if the upstream server is compromised and publishes a malicious update.
    Fix: Pin the version: npx @scope/[email protected]
  • medium MCP Rug Pull · line 272
    npx commands without a version suffix (e.g. @1.0.0) create a rug-pull risk if the upstream server is compromised and publishes a malicious update.
    Fix: Pin the version: npx @scope/[email protected]
  • medium MCP Rug Pull · line 273
    npx commands without a version suffix (e.g. @1.0.0) create a rug-pull risk if the upstream server is compromised and publishes a malicious update.
    Fix: Pin the version: npx @scope/[email protected]
  • medium MCP Rug Pull · line 274
    npx commands without a version suffix (e.g. @1.0.0) create a rug-pull risk if the upstream server is compromised and publishes a malicious update.
    Fix: Pin the version: npx @scope/[email protected]
  • medium MCP Rug Pull · line 791
    npx commands without a version suffix (e.g. @1.0.0) create a rug-pull risk if the upstream server is compromised and publishes a malicious update.
    Fix: Pin the version: npx @scope/[email protected]
How audits are shown
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 $0.00053 $0.07744
Opus 5.5 $0.00021 $0.03098
Sonnet 5.5 $0.00011 $0.01549
Haiku 4.5 $0.00005 $0.00774

Measured 1mo ago against content hash d1874a7729ad, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

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 1mo ago.

The scan reads SKILL.md. This mod also ships 8 executable files (references/cloudflare-worker-drizzle.ts, references/cloudflare-worker-kysely.ts, references/database-schema.ts, …), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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/skills/better-auth/SKILL.md · 804 lines

How it starts

The opening of the file, as written. The whole thing — 804 lines — stays where its author put it; the contents beside it link to each section on GitHub.

better-auth

Status: Production Ready Last Updated: 2026-04-08 Package: [email protected] (ESM-only) Dependencies: Drizzle ORM or Kysely (required for D1 complex use cases; D1 native support available in v1.5+)


Quick Start (5 Minutes)

Installation

Option 1: Drizzle ORM (Recommended)

bun add better-auth drizzle-orm drizzle-kit

Option 2: Kysely

bun add better-auth kysely @noxharmonium/kysely-d1

⚠️ v1.4.0+ Requirements

better-auth v1.4.0+ is ESM-only. Ensure:

package.json:

{
  "type": "module"
}

Upgrading from v1.3.x? Load references/migration-guide-1.4.0.md Upgrading from v1.4.x? Load references/migration-guide-1.5.0.md

⚠️ CRITICAL: D1 Adapter Requirements

v1.5.0+: D1 is now natively supported. Pass your D1 binding directly:

// ✅ SIMPLEST - D1 native (v1.5.0+)
import { betterAuth } from "better-auth";

const auth = betterAuth({
    database: env.DB, // D1 binding, auto-detected
});

For complex schemas, use Drizzle ORM:

// ✅ RECOMMENDED for complex schemas - Drizzle
import { drizzleAdapter } from "better-auth/adapters/drizzle";
import { drizzle } from "drizzle-orm/d1";

const auth = betterAuth({
    database: drizzleAdapter(drizzle(env.DB, { schema }), { provider: "sqlite" }),
});
// ❌ WRONG - This doesn't exist
import { d1Adapter } from 'better-auth/adapters/d1'

Minimal Setup (Cloudflare Workers + Drizzle)

1. Create D1 Database:

wrangler d1 create my-app-db

2. Define Schema (src/db/schema.ts):

import { integer, sqliteTable, text } from "drizzle-orm/sqlite-core";

export const user = sqliteTable("user", {
  id: text().primaryKey(),
  name: text().notNull(),
  email: text().notNull().unique(),
  emailVerified: integer({ mode: "boolean" }).notNull().default(false),
  image: text(),
});

export const session = sqliteTable("session", {
  id: text().primaryKey(),
  userId: text().notNull().references(() => user.id, { onDelete: "cascade" }),
  token: text().notNull(),
  expiresAt: integer({ mode: "timestamp" }).notNull(),
});

// See references/database-schema.ts for complete schema

Read the full file on GitHub · 804 lines

Files

What ships with it

37 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.

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 · 804 lines · 53 tokens per session scan A d1874a7729ad

Subscribe to this mod's changes

better-auth is a skill published in the GitHub repository secondsky/claude-skills (235 stars, last pushed 3d ago), licensed MIT. It adds 53 tokens to every session and 7,744 once invoked, about $0.0002 per session on Opus 5.5. 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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