Use when you need to design, review, or improve validation in Quarkus applications — including Bean Validation on JAX-RS resources, @Valid on parameters and CDI beans, constraint groups, @ConfigMapping validation, custom constraints, nested DTO validation, and ExceptionMapper-based error mapping. This should trigger for requests such as Add validation support in Quarkus; Review Quarkus validation rules; Improve request validation in Quarkus REST APIs; Add custom validation constraints in Quarkus
NewMaintained
Automatic
◆Coding pack
Last verified 8/20/2026
What it changes
Passed 21 of 22 test cases with the skill, and 21 of 22 without it.
Without skill95%
With skill95%
Checks it passed that the model alone missed
Recommends running compile command using ./mvnw compile or mvn compile before applying changes
1 fixed20 passed either way0 still failing1 broke
Pass-rate lift
0 pp
Tokens
-1%
Agent turns
0%
Response time
-26%
Model gemini-3.6-flashMeasured 8/20/2026v121 of 22 cases passed with skill
Tokens, turns and time describe resource use, not a dollar price.
See it in action
A test case the skill fixed. Same model, same prompt, with and without the skill.
Prompt
I need to add request DTO validation annotations to a Quarkus REST endpoint using Jakarta Bean Validation. Before editing any source files in the project, what initial build step should be executed to ensure the project starts in a valid state?
What was checked, without and with the skill
Checked
Without skill
With skill
Recommends running compile command using ./mvnw compile or mvn compile before applying changes
Missed
Passed
case-01 · gemini-3.6-flash · 8/20/2026 · answers are capped and redacted
What's inside
The instructions your model reads when the skill loads.
SKILL.md53 lines2 files
Quarkus Validation Guidelines
Apply Quarkus validation best practices at REST boundaries.
What is covered in this Skill?
Bean Validation annotations on DTOs and command models
@Valid and boundary validation in Jakarta REST resources
Validation groups and custom constraints
Validation error mapping for client-safe responses
Consistent handling of invalid inputs across endpoints
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 Quarkus
Review Quarkus validation rules
Improve request validation in Quarkus REST APIs
Add custom validation constraints in Quarkus
Validate Quarkus @ConfigMapping properties
Improve validation error mapping with ExceptionMapper in Quarkus
Workflow
Read reference and assess project context
Read references/403-frameworks-quarkus-validation.md and inspect the current project setup before proposing changes.
Use when you need Kafka messaging in Quarkus with SmallRye Reactive Messaging — including channel/topic design, build-time Jackson serialization, typed @Channel/@Incoming, ack/failure strategies, retries/DLQ, idempotency, Dev Services, and Testcontainers integration tests. This should trigger for requests such as Add Kafka in Quarkus; Review Reactive Messaging consumers; Improve failure handling for Quarkus Kafka; Configure Quarkus Reactive Messaging Kafka channels; Add Quarkus Kafka failure str