An API is a long-lived agreement: mobile apps, partners, generated SDKs, jobs, and event consumers can all depend on details that are easy to overlook. This skill helps your agent begin with the consumer's job and the domain's meaning before naming a route or selecting a protocol.

It produces practical design artifacts for HTTP, GraphQL, RPC, events, webhooks, and streams. Your agent can document retries, errors, authorization boundaries, delivery semantics, compatibility risks, and a migration path instead of treating an OpenAPI file as the whole design.

What You Get

Contents	Provides
`SKILL.md`	A workflow from discovery through rollout and verification
`references/`	Protocol, schema, failure, event, evolution, testing, and source guidance
`templates/`	Fillable briefs, contracts, taxonomies, assessments, plans, and reviews

Quick Start

Ask your agent: Design an API contract for creating and listing invoices, including retry and migration behavior.

It should begin an API design brief, select an interface style from the workload, and produce a contract reviewable by consumers and implementers.

Triggers

Design or review a REST/HTTP, GraphQL, RPC, event, webhook, or streaming API
Write or improve OpenAPI or AsyncAPI contracts
Define pagination, errors, idempotency, concurrency, or rate/resource behavior
Assess a consumer-breaking API change, version an interface, or plan deprecation
Build a migration and rollback plan for an external interface

Requirements

No runtime dependencies or API keys. The skill links to public standards; validate tooling support before relying on a specific OpenAPI or AsyncAPI feature for code generation or documentation.