mayrlabs-security-backend

mayrlabs-security-backend is a skill for Claude Code, Codex from MayR-Labs/skills. It costs 25 tokens per session (535 once invoked), scanned A, original, MIT.

A set of rules for securing backend services, which are the server-side programs behind apps and APIs. It covers checking incoming data, verifying identity and permissions, and safely accessing databases.

In plain words
What is it for?
Use it when creating or reviewing APIs, request validation, login and access-control code, database queries, and server or database schemas.
Why use it?
It helps prevent common server problems such as injection attacks, unauthorized access to another user's data, and unsafe database queries. It gives agents explicit security checks to follow when building backend code.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: positional $N argument.

Good fit Use it when creating or reviewing APIs, request validation, login and access-control code, database queries, and server or database schemas.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/mayr-labs/skills/backend
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 MayR-Labs/skills --skill backend
Clone the repo
git clone --depth 1 https://github.com/MayR-Labs/skills

Made for: Claude Code, Codex.

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 mayrlabs-security-backend

README.md
[![agentmods](https://agentmods.dev/badge/skills/mayr-labs/skills/backend/github.svg)](https://agentmods.dev/skills/mayr-labs/skills/backend)
Your own site
<a href="https://agentmods.dev/skills/mayr-labs/skills/backend"><img src="https://agentmods.dev/badge/skills/mayr-labs/skills/backend/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 mayrlabs-security-backend

Your own site · 80×15
<a href="https://agentmods.dev/skills/mayr-labs/skills/backend"><img src="https://agentmods.dev/badge/skills/mayr-labs/skills/backend.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 25 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 535 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.
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 $0.00025 $0.00535
Opus 5.5 $0.00010 $0.00214
Sonnet 5.5 $0.00005 $0.00107
Haiku 4.5 $0.00003 $0.00053

Measured 12d ago against content hash 148f865f7296, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

mayrlabs-security-backend 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.

collection/security/backend/SKILL.md · 79 lines

How it starts

The opening of the file, as written. The whole thing — 79 lines — stays where its author put it; the contents beside it link to each section on GitHub.

MayR Labs Security Doctrine: Backend

Purpose

To fortify server-side applications, APIs, and databases against injection, unauthorized access, and mass data extraction.

Audience

Backend engineers and AI agents scaffolding APIs, servers, or database schemas.

Core Rules & Constraints

1. Input Validation & Sanitization

  • Strict Typing: All incoming requests (params, body, headers, queries) must be validated using robust parsing libraries (e.g., Zod, Joi).
  • Reject Unrecognized Data: Strip or reject properties that are not explicitly defined in the schema.

2. Database Security (SQL/NoSQL Injection)

  • Parameterized Queries: Never concatenate strings to build queries. Use an ORM (Prisma, TypeORM) or strictly parameterized statements.
  • Ensure Object Relational Mappers (ORMs) do not blindly pass unsanitized query parameters to operations like findMany.

3. Authentication & Authorization

  • Implement explicit identity validation.
  • BOLA Prevention: (Broken Object Level Authorization). Always assert that the currently authenticated user has the necessary ownership or permissions to access the requested resource ID.
  • Verify JWTs computationally using asymmetric keys (RS256) where applicable and always validate the aud (audience) and exp (expiration).

4. Rate Limiting & Abuse Prevention

  • Enforce rate limits by IP, user ID, or API key to prevent brute forcing and denial-of-service (DoS).

Examples & References

❌ Insecure Database Query

// BANNED: SQL Injection vulnerability
db.query(`SELECT * FROM users WHERE email = '${req.body.email}'`);

✅ Secure Validation & Query

import { z } from 'zod';

const schema = z.object({ email: z.string().email() });
const { email } = schema.parse(req.body);

// Parameterized
await db.query(`SELECT * FROM users WHERE email = $1`, [email]);

Inputs & Outputs

  • Input: Implicit when writing API routes, database models, or middleware.
  • Output: Output will feature schema validation, explicit auth checks, and safe query methodologies.

Read the full file on GitHub · 79 lines

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. 12d ago First seen · 79 lines · 25 tokens per session scan A 148f865f7296

Subscribe to this mod's changes

mayrlabs-security-backend is a skill published in the GitHub repository MayR-Labs/skills (0 stars, last pushed 18d ago), licensed MIT. It adds 25 tokens to every session and 535 once invoked, about $0.0001 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 2026-10-02.

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