502 Frameworks Micronaut REST Agent Skill

Micronaut REST API Guidelines

Apply REST design principles for Micronaut HTTP applications.

What is covered in this Skill?

• Semantic HTTP with @Get/@Post/@Put/@Patch/@Delete and HttpResponse status control
• Resource-oriented paths and stable DTO contracts
• @Valid on request bodies with Bean Validation
• Centralized error mapping (ExceptionHandler / problem JSON when applicable)
• Pagination with Pageable and bounded sizes
• OpenAPI contract file (API-first) and OpenAPI Generator for server stubs
• Security annotations (@Secured) on sensitive routes
• Idempotency-Key for retried writes
• ETag / If-Match for optimistic concurrency
• Cache-Control discipline
• API versioning patterns
• ISO-8601 time types in DTOs

Scope: Apply recommendations based on the reference rules and good/bad code examples.

Constraints

Compile before REST refactors; verify after.

• MANDATORY: Run ./mvnw compile or mvn compile before applying any change
• SAFETY: If compilation fails, stop immediately
• VERIFY: Run ./mvnw clean verify or mvn clean verify after applying improvements
• BEFORE APPLYING: Read the reference for detailed rules and examples
• EDGE CASE: If request scope is ambiguous, stop and ask a clarifying question before applying changes
• EDGE CASE: If required inputs, files, or tooling are missing, report what is missing and ask whether to proceed with setup guidance

When to use this skill

• Review or improve Micronaut @Controller REST APIs
• Add validation, error handling, or align controllers with the OpenAPI contract on Micronaut HTTP layer
• Design Micronaut controllers and DTO validation
• Add Micronaut exception handlers and Problem Details responses
• Improve pagination filtering or OpenAPI alignment in Micronaut APIs

Workflow

• Read reference and assess project context

Read references/502-frameworks-micronaut-rest.md and inspect the current project setup before proposing changes.

• Gather scope and decide target improvements

Identify requested outcomes, constraints, and the minimum safe set of changes to apply.

• Apply framework-aligned changes

Implement or refactor configuration/code following the reference patterns and project conventions.

• Run verification and report results

Execute appropriate build/tests and summarize what changed, what was verified, and any follow-up actions.

Reference

For detailed guidance, examples, and constraints, see references/502-frameworks-micronaut-rest.md.