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 yultyyev/better-auth-firestore --skill firestore-better-authgit clone --depth 1 https://github.com/yultyyev/better-auth-firestoreWrote 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/yultyyev/better-auth-firestore/firestore-better-auth)<a href="https://agentmods.dev/skills/yultyyev/better-auth-firestore/firestore-better-auth"><img src="https://agentmods.dev/badge/skills/yultyyev/better-auth-firestore/firestore-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/yultyyev/better-auth-firestore/firestore-better-auth"><img src="https://agentmods.dev/badge/skills/yultyyev/better-auth-firestore/firestore-better-auth.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector warn
SkillSpector: 6 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 108 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 112 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 113 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 124 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 219 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 186 Docker image references without a specific tag (:latest is implicit) or digest (@sha256:...) can be silently replaced by a malicious image.Fix: Pin the image: image:tag or image@sha256:abc123
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 | $0.00100 | $0.02667 |
| Opus 5 | $0.00050 | $0.01333 |
| Sonnet 5 | $0.00020 | $0.00533 |
| Haiku 4.5 | $0.00010 | $0.00267 |
Grade A, and why
firestore-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 10d 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 — 236 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Firestore Adapter for Better Auth
better-auth-firestore is the Firestore database adapter for Better Auth. It stores users, sessions, accounts, and verification tokens in Firestore using the Firebase Admin SDK.
Package: better-auth-firestore — GitHub · npm
Install
pnpm add better-auth-firestore firebase-admin better-auth
Minimal setup
import { firestoreAdapter } from "better-auth-firestore";
import { betterAuth } from "better-auth";
import { getFirestore } from "firebase-admin/firestore";
export const auth = betterAuth({
database: firestoreAdapter({ firestore: getFirestore() }),
});
Full setup with credentials
import { betterAuth } from "better-auth";
import { firestoreAdapter, initFirestore } from "better-auth-firestore";
import { cert } from "firebase-admin/app";
const firestore = initFirestore({
credential: cert({
projectId: process.env.FIREBASE_PROJECT_ID!,
clientEmail: process.env.FIREBASE_CLIENT_EMAIL!,
privateKey: process.env.FIREBASE_PRIVATE_KEY!.replace(/\\n/g, "\n"),
}),
projectId: process.env.FIREBASE_PROJECT_ID!,
name: "better-auth",
});
export const auth = betterAuth({
database: firestoreAdapter({
firestore,
namingStrategy: "default", // or "snake_case"
collections: {
// users: "users",
// sessions: "sessions",
// accounts: "accounts",
// verificationTokens: "verificationTokens",
},
}),
});
Options
| Option | Type | Default | Description |
|---|---|---|---|
firestore |
Firestore |
getFirestore() |
Firebase Admin Firestore instance |
namingStrategy |
"default" | "snake_case" |
"default" |
Collection naming convention |
collections |
object |
see below | Override individual collection names |
debugLogs |
boolean |
false |
Enable verbose query logging |
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.
- 10d ago First seen · 236 lines · 100 tokens per session scan A f7ef1e4759c4
firestore-better-auth is a skill published in the GitHub repository yultyyev/better-auth-firestore (9 stars, last pushed 9d ago), licensed MIT. It adds 100 tokens to every session and 2,667 once invoked, about $0.0005 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 2026-08-31.
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