api-design SKILL.md skillA

api-design from ericrisco/rsc-harness is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.

Install it, pinned
mdr add ericrisco/rsc-harness/api-design@git:20260729.3ecb845

Pins git:20260729.3ecb845 in mdr.lock. Pin the fingerprint instead.

Audit grade
A, 17 of 17 checks passed
Kind
SKILL.md skill
Repository
ericrisco/rsc-harness
Path
skills/api-design/SKILL.md
Versions recorded
2
Latest version
git:20260729.3ecb845, committed Jul 29, 2026
First version recorded
Jun 2, 2026
Size
12,416 bytes
Repository stars
236
License
MIT

Use when settling the contract of an API you expose, before implementation: resources/URLs, REST vs GraphQL, versioning, one RFC 9457 error envelope, pagination, idempotency — emitted as OpenAPI 3.1. NOT implementing the endpoints (that is `fastapi`/`nestjs`/`go`/`nodejs`), NOT auth hardening (that is `secure-coding`), NOT consuming a third-party API (that is `api-connector-builder`).

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 design

## Your one job

You design the **contract** an API exposes. You do not write the handler. The deliverable is a set of decisions a backend skill can implement directly: resource shapes, URLs, methods, the status-code map, one error envelope, pagination params, versioning rules — ideally captured as an **OpenAPI 3.1** document.

When the user names a framework (FastAPI, NestJS, Go, Node), they own the build; you are pulled in for contract questions. Settle the contract first, then hand off (see [Handoff](#handoff)). Keep every decision framework-neutral: nothing here should mention an ORM, a router, or a DI container.

## REST vs GraphQL vs hybrid

Pick on traffic shape, not fashion. Decide once, write it down.

| Situation | Choose | Why |
|---|---|---|
| CRUD-ish resources, public API, HTTP caching matters | **REST** | URLs map to resources; CDN/proxy caching works on GET + ETag out of the box |
| Many client shapes, deep nested graphs, mobile over-fetch is real | **GraphQL** | one round-trip, client picks fields; no N endpoints per screen |
…

Read the whole file at its exact version.

How to install

The exact contents, by fingerprint
mdr add ericrisco/rsc-harness/api-design@sha256:4758665caa061a8f

The line at the top of this page pins the label git:20260729.3ecb845, 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 badge

[![mdr](https://markdownregistry.com/badge/art_kurtedjlx7pxmh5b.svg)](https://markdownregistry.com/a/art_kurtedjlx7pxmh5b)

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

Versions

The registry has recorded 2 versions of this file, between Jun 2, 2026 and Jul 29, 2026, about one every 57 days.

versioncommittedcommitsizeaudit
git:20260729.3ecb845 latest2026-07-29 3ecb845 12,416 BA view · diff
git:20260602.59a71762026-06-02 59a7176 13,132 BA 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 (12416 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

ericrisco/rsc-harness · 236 stars · license MIT · pushed 2026-10-21 · branch main

API

GET https://markdownregistry.com/api/v1/artifacts/art_kurtedjlx7pxmh5b
GET https://markdownregistry.com/api/v1/resolve?ref=ericrisco/rsc-harness/api-design
GET https://markdownregistry.com/api/v1/blob/4758665caa061a8f1806ad2114acc5b9896c258fead41ac743730054c8dee239

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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