| name | api |
| description | Corrects the 13 most common API design mistakes agents make — grounded in Geewax, Amundsen, Ousterhout, Kleppmann, and Gough/Bryant |
| version | 2.0.0 |
| type | knowledge |
| layer | domain |
| requires | {"sage":">=1.0.0"} |
| activates-when | {"detected":["express","fastify","koa","hono","django","flask","rails","spring","gin","echo","actix-web","axum"]} |
| tags | ["express","fastify","koa","hono","django"] |
api
Layer 1 — Domain Foundation (v2.0)
Corrects the 13 most common API design mistakes agents make, grounded in
5 authoritative sources:
- Geewax (API Design Patterns) — cursor pagination, error structure, idempotency, request deduplication
- Amundsen (RESTful Web API Cookbook) — PUT for idempotent creates, HTTP method semantics
- Ousterhout (Philosophy of Software Design) — information hiding, define errors out of existence, different layer/different abstraction
- Kleppmann (Designing Data-Intensive Applications) — network failures are normal, batch processing, data integrity
- Gough/Bryant (Mastering API Architecture) — schema validation, API lifecycle, backward compatibility, deprecation
What's Included
| Type | Count | Coverage |
|---|
| Patterns | 13 | Error envelope, input validation, cursor pagination, batch queries, auth-first, URL conventions, rate limiting, idempotent writes, separate representation, versioning, HTTP status codes, structured logging, health endpoints |
| Anti-patterns | 9 | Inconsistent errors, trusting input, returning all records, N+1 loops, bolt-on auth, non-idempotent creates, leaking DB internals, 200-with-error-body, no versioning plan |
| Constitution | 11 | principles |
Every pattern includes code examples showing wrong vs right approaches.
Every anti-pattern includes root cause explaining WHY agents default to the wrong behavior.
