Lists multiple specific concrete actions: defining API schemas, database schemas, REST/GraphQL endpoints, server-side validation, authentication, migrations, and backend logic. These are concrete, actionable capabilities.

Clearly answers both 'what' (defining APIs, database schemas, server logic, authentication, migrations) and 'when' with an explicit 'Use quando' clause and a dedicated 'Trigger em' list providing specific activation keywords.

Excellent coverage of natural trigger terms including both general terms ('API', 'endpoint', 'banco de dados', 'backend', 'servidor') and specific technologies ('JWT', 'Prisma', 'PostgreSQL', 'Node.js', 'Express', 'NestJS', 'ORM'). These are terms users would naturally use when requesting backend work.

While the backend focus is clear, terms like 'API', 'banco de dados', and 'validação' could overlap with frontend API consumption skills, database administration skills, or full-stack skills. The scope is broad enough ('qualquer lógica de backend') that it could conflict with more specialized backend skills.

The skill contains substantial useful content but is quite long (~300+ lines). Some sections like 'Quando Usar/Não Usar', 'Entradas/Saídas Esperadas', 'Evidencia de Conclusao', 'Código Limpo', and 'Integração com Pipeline' add marginal value and could be trimmed. The anti-rationalization table, while useful, adds bulk. However, the code examples themselves are lean and purposeful.

The skill provides fully executable, copy-paste ready code examples throughout: Prisma schema, Zod validators, Express middleware for validation/auth/error handling, a base service pattern, and concrete API endpoint patterns. The auth flow is step-by-step with specific implementation details. The migration strategy includes a concrete checklist.

The authentication flow is clearly sequenced with numbered steps, and the migration strategy includes a good zero-downtime checklist with rollback instructions. However, there's no overall workflow for creating a new backend feature end-to-end (e.g., define schema → create migration → validate migration → implement service → add endpoints → test → handoff). The migration section mentions testing in staging but lacks explicit validation checkpoints for the broader development process.

The skill references external files well (GLOBAL.md, various policies, docs/skill-guides/backend-api.md) and mentions consulting the guide 'apenas quando necessario'. However, the SKILL.md itself is quite long with extensive inline code examples that could be split into referenced files. The Prisma schema, middleware patterns, and service patterns could live in separate reference files, keeping the SKILL.md as a concise overview.