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 KunanonJ/ai-skills-hub --skill backend-security-codergit clone --depth 1 https://github.com/KunanonJ/ai-skills-hubWrote 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/kunanonj/ai-skills-hub/backend-security-coder)<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.
<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>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 | $0.00036 | $0.01905 |
| Opus 5.5 | $0.00014 | $0.00762 |
| Sonnet 5.5 | $0.00007 | $0.00381 |
| Haiku 4.5 | $0.00004 | $0.00191 |
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 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.
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.
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
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 · 161 lines · 36 tokens per session scan A 4297c8910245
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 $0.0001 per session on Opus 5.5. 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.
Other skills, from other repositories
api-verification
An API verification workflow that creates both an .http request file and a .cjs JavaScript file, then runs an automation script to test them. An API is an interface through which software exchanges requests and responses.
api-contract-architecture
An architecture guide for public APIs, including HTTP services, software-development kits, command-line tools, schemas, types, errors, pagination, filtering, and compatibility.
backend-domain-architecture
A review guide for backend and business-domain design. It examines business rules, workflows, permissions, APIs, transactions, consistency, repeated requests, compatibility, data boundaries, and service responsibilities.
distributed-systems-architecture
An architecture guide for distributed systems—software split across services that communicate over networks.
external-integration-architecture
A guide for designing connections to outside services such as web APIs, webhooks, and OAuth sign-ins. It focuses on keeping those connections separate and planning for failures.
api-runtime-verify
Verify a built backend HTTP surface at runtime: per route, record the response, assert it against the slice's acceptance behavior, and decide PASS/FAIL/BLOCKED. Do not use to review a contract before implementation (use api-contract-review or graphql-contract-review), write code (use implement-approved-slice), triage…