api-design

api-design is a skill for Claude Code from parisgroup-ai/imersao-ia-setup. It costs 62 tokens per session (666 once invoked), scanned A, original, MIT.

Guidance for designing and implementing web APIs—interfaces that let applications exchange data—with consistent URLs, responses, errors, and documentation.

In plain words
What is it for?
Use it when creating REST or GraphQL endpoints, backend services, API routes, or webhooks, including versioning and pagination.
Why use it?
It prevents each endpoint from behaving differently, making the API easier for clients to use and maintain.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the imersao plugin — 51 skills, 7 commands shipped together

Good fit Use it when creating REST or GraphQL endpoints, backend services, API routes, or webhooks, including versioning and pagination.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/parisgroup-ai/imersao-ia-setup/api-design
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 parisgroup-ai/imersao-ia-setup --skill api-design
Clone the repo
git clone --depth 1 https://github.com/parisgroup-ai/imersao-ia-setup

Made for: Claude Code.

Or install imersao, the plugin that ships this one along with the rest of its 51 skills, 7 commands.

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 api-design

README.md
[![agentmods](https://agentmods.dev/badge/skills/parisgroup-ai/imersao-ia-setup/api-design/github.svg)](https://agentmods.dev/skills/parisgroup-ai/imersao-ia-setup/api-design)
Your own site
<a href="https://agentmods.dev/skills/parisgroup-ai/imersao-ia-setup/api-design"><img src="https://agentmods.dev/badge/skills/parisgroup-ai/imersao-ia-setup/api-design/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 api-design

Your own site · 80×15
<a href="https://agentmods.dev/skills/parisgroup-ai/imersao-ia-setup/api-design"><img src="https://agentmods.dev/badge/skills/parisgroup-ai/imersao-ia-setup/api-design.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 62 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 666 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 $0.00062 $0.00666
Opus 5 $0.00031 $0.00333
Sonnet 5 $0.00012 $0.00133
Haiku 4.5 $0.00006 $0.00067

Measured 11d ago against content hash b6fec8849d6c, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

api-design 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 11d 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.

plugins/imersao/skills/api-design/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.

API Design Skill

This skill ensures every API is consistent, well-documented, and follows industry best practices.

URL Structure

/api/v1/{resource}                    # Collection
/api/v1/{resource}/{id}               # Single item
/api/v1/{resource}/{id}/{sub-resource}  # Nested resource

Rules:

  • Use plural nouns: /users, /orders, /products
  • Use kebab-case for multi-word: /order-items
  • Max 2 levels of nesting

HTTP Methods

Method Purpose Idempotent Safe
GET Retrieve Yes Yes
POST Create No No
PUT Replace Yes No
PATCH Update Yes No
DELETE Remove Yes No

Response Format

Success

{
  "data": { },
  "meta": {
    "requestId": "req_xyz789",
    "timestamp": "2024-01-15T10:30:00Z"
  }
}

Error

{
  "error": {
    "code": "VALIDATION_ERROR",
    "message": "Invalid input data",
    "details": [
      { "field": "email", "message": "Must be valid email" }
    ]
  },
  "meta": { "requestId": "req_xyz789" }
}

Status Codes

Code When to Use
200 Successful GET, PUT, PATCH
201 Successful POST (created)
204 Successful DELETE
400 Bad request
401 Not authenticated
403 Not authorized
404 Not found
409 Conflict
422 Validation failed
429 Rate limited
500 Server error

Pagination

{
  "data": [...],
  "pagination": {
    "page": 1,
    "perPage": 20,
    "total": 150,
    "totalPages": 8,
    "hasNext": true,
    "hasPrev": false
  }
}

Filtering & Sorting

GET /api/v1/users?status=active&sort=-createdAt&fields=id,name

Checklist

  • URLs use plural nouns and kebab-case
  • Correct HTTP methods for each operation
  • Consistent response envelope
  • Proper status codes
  • Pagination on all list endpoints
  • Validation with detailed errors
  • Rate limiting headers
  • OpenAPI documentation

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. 11d ago First seen · 112 lines · 62 tokens per session scan A b6fec8849d6c

Subscribe to this mod's changes

api-design is a skill published in the GitHub repository parisgroup-ai/imersao-ia-setup (1 stars, last pushed 29d ago), licensed MIT. It adds 62 tokens to every session and 666 once invoked, about $0.0003 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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