vnx-orchestration: Skill for Claude Code

.claude/skills/backend-developer/SKILL.md

backend-developer is a skill for Claude Code from Vinix24/vnx-orchestration. It costs 16 tokens per session (1,428 once invoked), scanned B, original, MIT.

A guide for building the server-side part of applications, including data handling, business rules, and web endpoints. It covers reliability, security, database design, testing, and API contracts—the agreed format for requests and responses.

In plain words
What is it for?
Use it to build features such as authentication services, data-processing pipelines, real-time event handlers, and REST APIs. It also helps with validation, logging, error handling, database queries, rate limits, and integration tests.
Why use it?
It gives structure for avoiding common backend problems such as invalid input, unclear errors, insecure database queries, broken authentication, and unreliable services. It also helps keep server behavior consistent as the application grows.

Skill for Claude Code

Written for Claude Code: allowed-tools in frontmatter. Also seen: mentions Codex.

This is Vinix24/vnx-orchestration's own configuration. It tells Claude Code how to work on vnx-orchestration itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything vnx-orchestration configures →

Reuse

Borrowing it

Nothing to install: this file belongs to Vinix24/vnx-orchestration. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/Vinix24/vnx-orchestration/main/.claude/skills/backend-developer/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/Vinix24/vnx-orchestration

Made for: Claude Code.

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-developer

README.md
[![agentmods](https://agentmods.dev/badge/skills/vinix24/vnx-orchestration/backend-developer/github.svg)](https://agentmods.dev/skills/vinix24/vnx-orchestration/backend-developer)
Your own site
<a href="https://agentmods.dev/skills/vinix24/vnx-orchestration/backend-developer"><img src="https://agentmods.dev/badge/skills/vinix24/vnx-orchestration/backend-developer/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-developer

Your own site · 80×15
<a href="https://agentmods.dev/skills/vinix24/vnx-orchestration/backend-developer"><img src="https://agentmods.dev/badge/skills/vinix24/vnx-orchestration/backend-developer.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 16 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,428 The whole file, excluding the scripts and references it only reads on demand.
Security scan B 1 finding. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 1 finding, up to high

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 →

  • high System Prompt Leakage · line 95
    Skill contains instructions that could directly expose system prompts, internal rules, or hidden instructions to users or external parties.
    Fix: Remove any instructions that reveal, print, or output system prompts or internal rules. System instructions should never be exposed to end users.
How audits are shown
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 $0.00016 $0.01428
Opus 5.5 $0.00006 $0.00571
Sonnet 5.5 $0.00003 $0.00286
Haiku 4.5 $0.00002 $0.00143

Measured 25d ago against content hash b92a62cf83cc, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade B, and why

backend-developer scanned grade B with 1 finding 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 25d 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.

Asks the agent to reveal its instructionsmediumSystem prompt leakage

Directions to print, repeat or translate the system prompt extract configuration the operator did not intend to expose.

## Output Instructions
.claude/skills/backend-developer/SKILL.md · 112 lines

How it starts

The opening of the file, as written. The whole thing — 112 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Backend Developer

Create fault-tolerant, scalable server-side solutions with focus on reliability and security.

Core Responsibilities

  • Design data models and schemas
  • Implement business logic with tests
  • Create API endpoints with validation
  • Add error handling and logging
  • Optimize database queries
  • Document API contracts

Core Principles

  • Reliability First: Build fault-tolerant systems
  • Security by Default: Validate inputs, sanitize outputs
  • Performance Aware: Optimize queries, cache strategically
  • API Design: RESTful conventions, clear contracts

Examples

  • "Implement user authentication service"
  • "Create data processing pipeline"
  • "Build real-time event handler"

Guidelines

  • Error Handling: Graceful degradation, meaningful messages
  • Logging: Structured logs with correlation IDs
  • Security: Input validation, SQL injection prevention
  • Testing: Unit tests >80%, integration tests
  • Database: Normalized design, indexed queries

API Development Standards

  • Clear resource naming (/users, /products)
  • HTTP status codes correctly used
  • Request/response validation
  • Rate limiting implemented
  • Authentication/authorization checks

Performance Targets

  • Response time <200ms p95
  • Database queries <50ms
  • Connection pooling configured
  • Caching strategy defined
  • Background jobs for heavy tasks

Quality Requirements

  • PR under 300 lines
  • Include unit and integration tests
  • Update API documentation
  • No breaking changes without versioning
  • Follow existing patterns

Codex Defense Checklist (mandatory before commit)

These patterns recur in codex_gate findings. Apply preemptively.

File I/O

  • Atomic writes: any rewrite of a persistent file (YAML, NDJSON, JSON config, schema files) MUST write to <path>.tmp then os.replace(tmp, path). Never open(path, 'w') directly on canonical state.
  • fcntl.flock for shared NDJSON: any read-then-rewrite of an NDJSON file consumed by live appenders MUST acquire fcntl.flock(fd, fcntl.LOCK_EX) on the same lock the appenders use. Hold through atomic rename.
  • Subprocess stdin writes: wrap proc.stdin.write() in try: ... except BrokenPipeError: return AdapterResult(status='failed', ...). Provider startup-failures must surface as structured failures, not raised exceptions.

Read the full file on GitHub · 112 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. 25d ago Changed b92a62cf83cc
  2. 1mo ago First seen · 112 lines · 16 tokens per session scan B 3013c7494c4b

Subscribe to this mod's changes

backend-developer is a skill published in the GitHub repository Vinix24/vnx-orchestration (62 stars, last pushed today), licensed MIT. It adds 16 tokens to every session and 1,428 once invoked, about $0.0001 per session on Opus 5.5. A static security scan graded it B with 1 finding (asks the agent to reveal its instructions). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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