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 agentmods add commands/secondsky/claude-skills/better-auth-add-plugingit 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/commands/secondsky/claude-skills/better-auth-add-plugin)<a href="https://agentmods.dev/commands/secondsky/claude-skills/better-auth-add-plugin"><img src="https://agentmods.dev/badge/commands/secondsky/claude-skills/better-auth-add-plugin.svg" alt="Measured on agentmods" 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 | $0.00025 | $0.01467 |
| Opus 5 | $0.00013 | $0.00733 |
| Sonnet 5 | $0.00005 | $0.00293 |
| Haiku 4.5 | $0.00003 | $0.00147 |
Grade A, and why
better-auth:add-plugin 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 6d 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 — 279 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Add better-auth Plugin
This command adds a plugin to an existing better-auth configuration.
Usage
/better-auth-add-plugin <plugin-name>
Supported Plugins
| Plugin | Description |
|---|---|
2fa / two-factor |
Two-factor authentication (TOTP) |
passkeys |
WebAuthn/Passkeys |
magic-link |
Passwordless magic links |
email-otp |
Email-based OTP codes |
anonymous |
Anonymous/guest users |
organizations |
Multi-tenancy support |
sso / saml |
SSO/SAML integration |
scim |
SCIM user provisioning |
admin |
Admin dashboard |
api-key |
API key authentication |
bearer |
Bearer token support |
jwt |
JWT token plugin |
oidc |
OIDC provider |
stripe |
Stripe payments |
polar |
Polar payments |
Process
Step 1: Locate Configuration
Find the existing auth configuration:
src/auth.tslib/auth.tsserver/auth.ts
Find the client configuration:
src/lib/auth-client.tslib/auth-client.ts
Step 2: Add Server Plugin
Based on the plugin, add the appropriate import and configuration:
Two-Factor Authentication
import { twoFactor } from "better-auth/plugins";
plugins: [
twoFactor({
issuer: "Your App Name",
}),
],
Passkeys
import { passkey } from "@better-auth/passkey"; // extracted package (v1.5+)
plugins: [
passkey({
rpID: "your-domain.com",
rpName: "Your App",
origin: "https://your-domain.com",
}),
],
Magic Links
import { magicLink } from "better-auth/plugins";
plugins: [
magicLink({
sendMagicLink: async ({ email, token, url }) => {
// TODO: Implement email sending
await sendEmail({ to: email, subject: "Sign in", html: `<a href="${url}">Click to sign in</a>` });
},
}),
],
Organizations
import { organization } from "better-auth/plugins";
plugins: [
organization({
allowUserToCreateOrganization: true,
}),
],
API Keys
import { apiKey } from "@better-auth/api-key"; // extracted package (v1.5+)
plugins: [
apiKey({
prefix: "sk_",
}),
],
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.
- 6d ago First seen · 279 lines · 25 tokens per session scan A 0e1540837ab0
better-auth:add-plugin is a command published in the GitHub repository secondsky/claude-skills (214 stars, last pushed 3d ago), licensed MIT. It adds 25 tokens to every session and 1,467 once invoked, about $0.0001 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 commands, from other repositories
correlate
Find related failures through pattern matching.
diff
Compare two command outputs with intelligent diff.
open
Open/retrieve an offloaded output by ID or shortcut.
search
Search through offloaded outputs with hard caps.
stats
Show FewWord session statistics with rich output and token savings.
config
Show effective FewWord configuration with sources.