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 secondsky/claude-skills --skill better-authgit clone --depth 1 https://github.com/secondsky/claude-skillsWrote 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/secondsky/claude-skills/better-auth)<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.
<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>- Socket pass
- Snyk pass
- NVIDIA SkillSpector warn
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]
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 | $0.00053 | $0.07744 |
| Opus 5.5 | $0.00021 | $0.03098 |
| Sonnet 5.5 | $0.00011 | $0.01549 |
| Haiku 4.5 | $0.00005 | $0.00774 |
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.
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.
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
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.
- assets/auth-flow-diagram.md 24 KB
- references/advanced-features.md 15 KB
- references/cloudflare-worker-drizzle.ts 13 KB runs code
- references/cloudflare-worker-kysely.ts 9.7 KB runs code
- references/configuration-guide.md 11 KB
- references/database-schema.ts 11 KB runs code
- references/databases/mongodb.md 5.3 KB
- references/databases/mysql.md 6.8 KB
- references/databases/postgresql.md 8.4 KB
- references/error-catalog.md 13 KB
- references/framework-comparison.md 8.2 KB
- references/frameworks/api-frameworks.md 9.2 KB
- references/frameworks/expo-mobile.md 8.7 KB
- references/frameworks/nextjs.md 5.4 KB
- references/frameworks/nuxt.md 6.0 KB
- references/frameworks/remix.md 6.1 KB
- references/frameworks/sveltekit.md 6.3 KB
- references/integrations/electron.md 8.2 KB
- references/migration-guide-1.4.0.md 23 KB
- references/migration-guide-1.5.0.md 6.3 KB
- references/nextjs/postgres-example.ts 4.0 KB runs code
- references/nextjs/README.md 1.1 KB
- references/plugins/api-tokens.md 10 KB
- references/plugins/authentication.md 9.2 KB
- references/plugins/enterprise.md 9.1 KB
- references/plugins/payments.md 8.0 KB
- references/plugins/sso.md 9.4 KB
- references/plugins/test-utils.md 5.5 KB
- references/react-client-hooks.tsx 13 KB
- references/setup-guide.md 8.9 KB
- references/v1.4-features.md 8.2 KB
- references/v1.5-features.md 11 KB
- references/v1.6-features.md 6.1 KB
- scripts/generate-secret.sh 2.0 KB runs code
- scripts/setup-d1-drizzle.sh 10 KB runs code
- scripts/test-auth-health.sh 2.1 KB runs code
- scripts/validate-config.ts 4.3 KB runs code
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.
- 1mo ago First seen · 804 lines · 53 tokens per session scan A d1874a7729ad
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.
Other skills, from other repositories
decide
A reusable decision procedure, and a copyable prototype for the guard that encodes it — derive the population, set one threshold by what being wrong costs, name the offender, and break it once to prove it can fail. Use when writing a check, guard, gate or validation of any kind, or when deciding whether something is…
remember
Record why something is the way it is — a decision and its reasoning, a lesson that cost time, or a standing constraint. Use when the reasoning behind a choice would be expensive to reconstruct later.
bootstrap
Set up chamnan in this repository for the first time — build the architecture index, measure how well the code describes itself, fill in missing file comments, and record a baseline. Run once per repo.
review
Review a change with what this repository knows about it — who depends on the file, which tests cover it, what broke here before, and what the repo has written down. Use before approving a diff, opening a PR, or when asked to review.
milestone
Record a change that reshaped the repository — what moved, why it was worth doing, and which areas it touched. Use after a migration, a rewrite, or a decision that changed how part of the system works.
why
Work out whether a failure is your machine or your code before debugging either, using the environment this repository has declared and the dependency map. Use when a test, build or command fails and the cause is not obvious from the error.