backend-api

backend-api is a skill for Claude Code, Codex from Ozzeron/prompt-pack. It costs 25 tokens per session (1,115 once invoked), scanned A, original, MIT.

A guide for building server-side application features such as API endpoints, database access, authentication, permissions, validation, and error handling. It follows the project's existing technology and patterns.

In plain words
What is it for?
Use it for new API routes, database queries or migrations, login and session flows, authorization, and business logic that saves or retrieves data.
Why use it?
It gives the client and server a clear agreement about requests, responses, and errors while keeping security and correctness in view. It also separates server work from user-interface and deployment work.

Skill for Claude CodeCodex

Part of the backend plugin — 13 skills shipped together , and of supabase, fullstack, all-skills

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.

agentmods
npx agentmods add skills/ozzeron/prompt-pack/backend-api
Any agent
npx skills add Ozzeron/prompt-pack --skill backend-api
Clone the repo
git clone --depth 1 https://github.com/Ozzeron/prompt-pack

Made for: Claude Code, Codex.

Or install backend, the plugin that ships this one along with the rest of its 13 skills.

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-api

README.md
[![agentmods](https://agentmods.dev/badge/skills/ozzeron/prompt-pack/backend-api.svg)](https://agentmods.dev/skills/ozzeron/prompt-pack/backend-api)
Your own site
<a href="https://agentmods.dev/skills/ozzeron/prompt-pack/backend-api"><img src="https://agentmods.dev/badge/skills/ozzeron/prompt-pack/backend-api.svg" alt="Measured on agentmods" 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 1,115 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00025 $0.01115
Opus 5 $0.00013 $0.00558
Sonnet 5 $0.00005 $0.00223
Haiku 4.5 $0.00003 $0.00112

Measured 5d ago against content hash 26ffacaf174d, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

backend-api 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 5d 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.

prompts/architecture/backend-api/SKILL.md · 108 lines

How it starts

The opening of the file, as written. The whole thing — 108 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Backend API Developer

You build server-side features: endpoints, data access, auth, error handling. Pragmatic over clever. Security and correctness are non-negotiable; performance follows evidence, not premonition. You match the project's existing stack and patterns instead of introducing your own.

When to use

  • New endpoint or API surface
  • Database queries, schemas, migrations
  • Auth flows (login, session, tokens, permissions)
  • Server-side business logic with data persistence

Do not invoke for pure UI work, infrastructure choices (hosting, containers), or greenfield framework selection.

Scope

In scope:

  • API contract (method, path, request, response, errors)
  • Data layer (queries, transactions, indexes, migrations)
  • Auth and authorization checks
  • Input validation, output sanitization
  • Error responses and logging
  • Tests for the new code

Out of scope:

  • Frontend consumption code (specify the contract; consumer is separate)
  • Infrastructure (deployment, scaling, CDNs)
  • Framework swaps — work with what exists

Inherits

Token discipline (specific)

Inherit meta/token-discipline. Additionally:

  • Detect stack from package.json, pyproject.toml, go.mod, Cargo.toml, Gemfile, composer.json, etc. Read one of these.
  • Read existing route/controller files in the same area before adding new ones — match style.
  • Read schema or model files for tables you touch. Skip the rest.
  • Do not read migration history beyond the most recent few.
  • Do not open the test suite unless writing tests is part of the task.

Read the full file on GitHub · 108 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. 5d ago First seen · 108 lines · 25 tokens per session scan A 26ffacaf174d

Subscribe to this mod's changes

backend-api is a skill published in the GitHub repository Ozzeron/prompt-pack (8 stars, last pushed 1mo ago), licensed MIT. It adds 25 tokens to every session and 1,115 once invoked, about $0.0001 per session on Opus 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 2026-08-31.

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