api-and-interface-design SKILL.md skillA

api-and-interface-design from nota-america/forgecat-agent-profiles is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.

mdr add nota-america/forgecat-agent-profiles/api-and-interface-design@git:20260916.3a6b22e

Pins git:20260916.3a6b22e in mdr.lock. Pin the fingerprint instead.

Audit grade

A, 17 of 17 checks passed

Kind

SKILL.md skill

Repository

nota-america/forgecat-agent-profiles

Path

profiles/addyosmani/agent-skills/for-codex/.agents/skills/api-and-interface-design/SKILL.md

Versions recorded

2

Latest version

git:20260916.3a6b22e, committed Sep 16, 2026

First version recorded

Jun 10, 2026

Size

14,884 bytes

Repository stars

93

License

Apache-2.0

Guides stable API and interface design. Use when designing APIs, module boundaries, or any public interface. Use when creating REST or GraphQL endpoints, defining type contracts between modules, or establishing boundaries between frontend and backend.

Collected from public GitHub. Every version is saved exactly as it was and never changes. Install it at an exact version with the mdr tool, and every file is checked before it reaches your agent. The main file is checked against the SHA-256 fingerprint recorded here, and the others against the fingerprints GitHub keeps for its source commit. The automatic checks below grade the latest version, and the same checks always give the same file the same grade.

What the file says

# API and Interface Design

## Overview

Design stable, well-documented interfaces that are hard to misuse. Good interfaces make the right thing easy and the wrong thing hard. This applies to REST APIs, GraphQL schemas, module boundaries, component props, and any surface where one piece of code talks to another.

## When to Use

- Designing new API endpoints
- Defining module boundaries or contracts between teams
- Creating component prop interfaces
- Establishing database schema that informs API shape
- Changing existing public interfaces

## Core Principles

### Hyrum's Law

> With a sufficient number of users of an API, all observable behaviors of your system will be depended on by somebody, regardless of what you promise in the contract.

This means: every public behavior — including undocumented quirks, error message text, timing, and ordering — becomes a de facto contract once users depend on it. Design implications:

- **Be intentional about what you expose.** Every observable behavior is a potential commitment.
- **Don't leak implementation details.** If users can observe it, they will depend on it.
…

Read the whole file at its exact version.

How to install

mdr add nota-america/forgecat-agent-profiles/api-and-interface-design@sha256:5dafd0c44a3aabf1

[![mdr](https://markdownregistry.com/badge/art_3a2pukett2jypf5t.svg)](https://markdownregistry.com/a/art_3a2pukett2jypf5t)

Versions

The registry has recorded 2 versions of this file, between Jun 10, 2026 and Sep 16, 2026, about one every 98 days.

Audit of the latest version

Source

API

GET https://markdownregistry.com/api/v1/artifacts/art_3a2pukett2jypf5t
GET https://markdownregistry.com/api/v1/resolve?ref=nota-america/forgecat-agent-profiles/api-and-interface-design
GET https://markdownregistry.com/api/v1/blob/5dafd0c44a3aabf11cae5bcb34f6fcc24dfa5c01ba6e0d3176bce997f4d68bc8

Your AI assistant does the legwork. You hear about the deals worth your word. Hand yours the standing instructions at modelranch.com and it joins the network that reads files like this one.

Guides: the SKILL.md format and its required fields · what to check before you install a skill · how to pin a skill to an exact version · where to find agent skills · keeping a team on the same skills · which agent file does what.

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