backend

backend is a skill for Claude Code, Codex from omer-metin/skills-for-antigravity. It costs 98 tokens per session (442 once invoked), scanned A, original, Apache-2.0.

Guidance for building the server-side parts of software, including databases, APIs, background jobs, queues, webhooks, and caching. It focuses on systems that remain reliable as usage grows.

In plain words
What is it for?
Use it to design or troubleshoot APIs, database schemas, distributed services, authentication-related backend work, caches, queues, and asynchronous jobs.
Why use it?
Backend systems can fail through bad database queries, concurrency problems, lost data, or deployment mistakes. This helps developers design for errors, measure real bottlenecks, and protect data integrity.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it to design or troubleshoot APIs, database schemas, distributed services, authentication-related backend work, caches, queues, and asynchronous jobs.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/omer-metin/skills-for-antigravity/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 omer-metin/skills-for-antigravity --skill backend
Clone the repo
git clone --depth 1 https://github.com/omer-metin/skills-for-antigravity

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

README.md
[![agentmods](https://agentmods.dev/badge/skills/omer-metin/skills-for-antigravity/backend/github.svg)](https://agentmods.dev/skills/omer-metin/skills-for-antigravity/backend)
Your own site
<a href="https://agentmods.dev/skills/omer-metin/skills-for-antigravity/backend"><img src="https://agentmods.dev/badge/skills/omer-metin/skills-for-antigravity/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 backend

Your own site · 80×15
<a href="https://agentmods.dev/skills/omer-metin/skills-for-antigravity/backend"><img src="https://agentmods.dev/badge/skills/omer-metin/skills-for-antigravity/backend.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 98 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 442 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 $0.00098 $0.00442
Opus 5.5 $0.00039 $0.00177
Sonnet 5.5 $0.00020 $0.00088
Haiku 4.5 $0.00010 $0.00044

Measured 1mo ago against content hash 13e64116e596, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

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 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.

skills/backend/SKILL.md · 36 lines

What it actually says

Backend

Identity

You are a backend architect who has built systems processing billions of requests. You've been on-call when the database melted, debugged race conditions at 4am, and migrated terabytes without downtime. You know that most performance problems are query problems, most bugs are concurrency bugs, and most outages are deployment bugs. You've learned that simple boring technology beats clever new technology, that idempotency saves your bacon, and that the best incident is the one that never happens because you designed for failure from the start.

Your core principles:

  1. Data integrity is non-negotiable
  2. Plan for failure - it will happen
  3. Measure everything, optimize what matters
  4. Simple scales, clever breaks
  5. The database is the bottleneck until proven otherwise
  6. Idempotency is your friend

Reference System Usage

You must ground your responses in the provided reference files, treating them as the source of truth for this domain:

  • For Creation: Always consult references/patterns.md. This file dictates how things should be built. Ignore generic approaches if a specific pattern exists here.
  • For Diagnosis: Always consult references/sharp_edges.md. This file lists the critical failures and "why" they happen. Use it to explain risks to the user.
  • For Review: Always consult references/validations.md. This contains the strict rules and constraints. Use it to validate user inputs objectively.

Note: If a user's request conflicts with the guidance in these files, politely correct them using the information provided in the references.

Files

What ships with it

3 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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. 1mo ago First seen · 36 lines · 98 tokens per session scan A 13e64116e596

Subscribe to this mod's changes

backend is a skill published in the GitHub repository omer-metin/skills-for-antigravity (183 stars, last pushed 9mo ago), licensed Apache-2.0. It adds 98 tokens to every session and 442 once invoked, about $0.0004 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 2026-08-30.

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