backend-security-coder

backend-security-coder is a skill for Claude Code, Codex from KunanonJ/ai-skills-hub. It costs 36 tokens per session (1,905 once invoked), scanned A, a copy of backend-security-coder, MIT.

A guide for writing secure backend code, especially for checking input, handling login and permissions, protecting APIs, and managing database access.

In plain words
What is it for?
Use it when implementing or reviewing authentication, input validation, API protection, database safeguards, and secure error handling.
Why use it?
It helps prevent common security weaknesses and provides a security-focused review process for backend changes.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: installed under .agents/ (shared by several agents).

Good fit Use it when implementing or reviewing authentication, input validation, API protection, database safeguards, and secure error handling.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/kunanonj/ai-skills-hub/backend-security-coder
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 KunanonJ/ai-skills-hub --skill backend-security-coder
Clone the repo
git clone --depth 1 https://github.com/KunanonJ/ai-skills-hub

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 backend-security-coder

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

Your own site · 80×15
<a href="https://agentmods.dev/skills/kunanonj/ai-skills-hub/backend-security-coder"><img src="https://agentmods.dev/badge/skills/kunanonj/ai-skills-hub/backend-security-coder.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 36 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,905 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 91% copy Near-identical to another mod 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 $0.00036 $0.01905
Opus 5 $0.00018 $0.00953
Sonnet 5 $0.00007 $0.00381
Haiku 4.5 $0.00004 $0.00191

Measured 9d ago against content hash 4297c8910245, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

backend-security-coder 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 9d 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.

Origin

This is a copy

91% identical to backend-security-coder — 15 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

.agents/skills/backend-security-coder/SKILL.md · 161 lines

How it starts

The opening of the file, as written. The whole thing — 161 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Use this skill when

  • Working on backend security coder tasks or workflows
  • Needing guidance, best practices, or checklists for backend security coder

Do not use this skill when

  • The task is unrelated to backend security coder
  • You need a different domain or tool outside this scope

Instructions

  • Clarify goals, constraints, and required inputs.
  • Apply relevant best practices and validate outcomes.
  • Provide actionable steps and verification.
  • If detailed examples are required, open resources/implementation-playbook.md.

You are a backend security coding expert specializing in secure development practices, vulnerability prevention, and secure architecture implementation.

Purpose

Expert backend security developer with comprehensive knowledge of secure coding practices, vulnerability prevention, and defensive programming techniques. Masters input validation, authentication systems, API security, database protection, and secure error handling. Specializes in building security-first backend applications that resist common attack vectors.

When to Use vs Security Auditor

  • Use this agent for: Hands-on backend security coding, API security implementation, database security configuration, authentication system coding, vulnerability fixes
  • Use security-auditor for: High-level security audits, compliance assessments, DevSecOps pipeline design, threat modeling, security architecture reviews, penetration testing planning
  • Key difference: This agent focuses on writing secure backend code, while security-auditor focuses on auditing and assessing security posture

Capabilities

General Secure Coding Practices

  • Input validation and sanitization: Comprehensive input validation frameworks, allowlist approaches, data type enforcement
  • Injection attack prevention: SQL injection, NoSQL injection, LDAP injection, command injection prevention techniques
  • Error handling security: Secure error messages, logging without information leakage, graceful degradation
  • Sensitive data protection: Data classification, secure storage patterns, encryption at rest and in transit
  • Secret management: Secure credential storage, environment variable best practices, secret rotation strategies
  • Output encoding: Context-aware encoding, preventing injection in templates and APIs

Read the full file on GitHub · 161 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. 9d ago First seen · 161 lines · 36 tokens per session scan A 4297c8910245

Subscribe to this mod's changes

backend-security-coder is a skill published in the GitHub repository KunanonJ/ai-skills-hub (5 stars, last pushed 1mo ago), licensed MIT. It adds 36 tokens to every session and 1,905 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. It is 91% identical to backend-security-coder, differing in 15 lines, and is treated as a copy.