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api-and-interface-design SKILL.md skillA

This file is byte-identical to the first copy the registry indexed, one of 6 indexed copies. Same content hash, so the same checks give both the same grade.

api-and-interface-design from aicodedecode/awesome-muse-skills is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.

Install it, pinned

mdr add aicodedecode/awesome-muse-skills/api-and-interface-design@git:20260927.806f3e1

Pins git:20260927.806f3e1 in mdr.lock. Pin the fingerprint instead.

Audit grade: A, 17 of 17 checks passed
Kind: SKILL.md skill
Repository: aicodedecode/awesome-muse-skills
Path: skills-imported/api-and-interface-design/SKILL.md
Versions recorded: 1
Latest version: git:20260927.806f3e1, committed Sep 27, 2026
Size: 14,884 bytes
Repository stars: 25
License: MIT

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

The exact contents, by fingerprint

mdr add aicodedecode/awesome-muse-skills/api-and-interface-design@sha256:5dafd0c44a3aabf1

The line at the top of this page pins the label git:20260927.806f3e1, which is what most people want. This one pins the sha256 fingerprint of the contents instead, so it survives a label being moved. Either way the exact version is written to mdr.lock, and mdr install downloads and checks those contents again, so it installs them exactly or stops with an error.

Badge

[![mdr](https://markdownregistry.com/badge/art_5besf4dhc2x22fnp.svg)](https://markdownregistry.com/a/art_5besf4dhc2x22fnp)

2 badge image fetches in 30 days. What the badge shows.

Versions

The registry has recorded 1 version of this file, committed on Sep 27, 2026.

version	committed	commit	size	audit
git:20260927.806f3e1 latest	2026-09-27	806f3e1	14,884 B	A	view

Audit of the latest version

A 17 of 17 checks passed. Fixed automatic checks with no AI involved, so the same checks give the same answer every run.

pass: Frontmatter block present
pass: Frontmatter declares a name
pass: Frontmatter declares a description
pass: Size between 200 bytes and 200 KB (14884 bytes)
pass: No zero-width or bidi control characters
pass: No instruction hidden inside an HTML comment
pass: No link to an exfiltration or paste host
pass: No credential-shaped string
pass: No instruction to send local credentials anywhere
pass: No text hidden with inline styles
pass: No prompt-injection phrasing
pass: No curl or wget piped into a shell
pass: No recursive delete of root, home or parent
pass: No instruction to read or print local credentials
pass: No base64 blob over 200 characters
pass: No link to a raw IP address
pass: No script tag

Source

GitHub

aicodedecode/awesome-muse-skills · 25 stars · license MIT · pushed 2026-10-10 · branch main

API

GET https://markdownregistry.com/api/v1/artifacts/art_5besf4dhc2x22fnp
GET https://markdownregistry.com/api/v1/resolve?ref=aicodedecode/awesome-muse-skills/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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