503 Frameworks Micronaut Validation

Micronaut Validation Guidelines

Apply Micronaut validation best practices at HTTP API boundaries.

What is covered in this Skill?

• Bean Validation annotations on DTOs and command models
• @Valid / @Validated usage in Micronaut controllers
• Validation groups and custom validators
• Consistent mapping of validation failures to 400 responses
• Safe and predictable validation error payloads

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

Constraints

Before applying validation changes, ensure the project compiles. After improvements, run full verification.

• 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

When to use this skill

• Add validation support in Micronaut
• Review Micronaut validation rules
• Improve request validation in Micronaut REST APIs
• Add custom validation constraints in Micronaut
• Validate Micronaut configuration properties
• Improve constraint violation handling in Micronaut

Workflow

• Read reference and assess project context

Read references/503-frameworks-micronaut-validation.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 validation-related 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/503-frameworks-micronaut-validation.md.