A guide for designing APIs, which are interfaces that let software systems communicate. It covers REST, GraphQL, gRPC, and Python library interfaces.

Use it to design API endpoints and schemas, authentication, pagination, error handling, federation, or Python library interfaces.

It helps settle the shape of endpoints, data formats, login rules, paging, errors, and service-to-service connections before implementation.

api-design — Plugin by viktorbezdek

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.

Claude Code

/plugin marketplace add viktorbezdek/skillstack

agentmods

npx agentmods add plugins/viktorbezdek/skillstack/api-design

Clone the repo

git clone --depth 1 https://github.com/viktorbezdek/skillstack

Made for: Claude Code.

Per session not measured What this adds to a session before it is invoked.

When invoked not measured Not applicable: nothing here is loaded into a session.

Security scan A 0 findings. Scan, not verified.

Origin original No closer match found in the catalogue.

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 yesterday.

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.

api-design/.claude-plugin/plugin.json · 21 lines

What it actually says

{
  "name": "api-design",
  "version": "1.2.24",
  "description": "Comprehensive API design skill for REST, GraphQL, gRPC, and Python library architectures. Design endpoints, schemas, authentication, pagination, error handling, and federation.",
  "author": {
    "name": "Viktor Bezdek",
    "url": "https://github.com/viktorbezdek"
  },
  "license": "MIT",
  "repository": "https://github.com/viktorbezdek/skillstack/tree/main/api-design",
  "keywords": [
    "claude-code",
    "skill",
    "API",
    "endpoint",
    "REST",
    "GraphQL",
    "gRPC"
  ]
}

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.

yesterday First seen · 21 lines scan A d5f9709b929f

Subscribe to this mod's changes

api-design is a plugin published in the GitHub repository viktorbezdek/skillstack (11 stars, last pushed 2mo ago), licensed MIT. Its token cost is not measured: this kind of file is read by the harness, not the model. 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.

Backend and APIs Languages agentic anthropic claude claude-code claude-skills skills

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google/skills · not measured

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api-design

Getting it into your agent

Grade A, and why

Nothing flagged

What it actually says

What this file has done since we first saw it

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