grape-idioms

name	grape-idioms
description	Grape APIs: endpoint design, param coercion, versioning, grape-entity. Triggers: "API versioning", "param coercion", "endpoint design", "Grape::Entity". Do NOT use for: Rails controllers.
user-invocable	false
effort	medium

Grape Idioms

Iron Laws

1. Define input contracts in params do.
2. Use declared(params, include_missing: false) or equivalent explicit shaping before passing data inward.
3. Keep endpoints thin and push business rules into application code.
4. Standardize error envelopes and auth behavior per version.

Good Defaults

• namespaced versioning
• rescue_from for predictable API errors
• presenters/entities only when they clarify response shape
• request specs for transport behavior

References

Need	Reference
declared params, versioning, entities, mounted-API patterns, error envelopes, JWT/OAuth auth, Rails integration	${CLAUDE_SKILL_DIR}/references/grape-patterns.md
JSON API patterns (Rails-side overlap)	${CLAUDE_PLUGIN_ROOT}/skills/rails-contexts/references/json-api-patterns.md