Use when you need Kafka messaging in Micronaut — including @KafkaClient and @KafkaListener design, @Serdeable serialization, topic/partition strategy, TestPropertyProvider integration tests, retries and dead-letter processing, and error handling. This should trigger for requests such as Add Kafka in Micronaut; Review Micronaut Kafka listeners; Improve retry and failure handling for Micronaut Kafka; Configure Micronaut Kafka clients listeners or SerDes; Add Micronaut Kafka retry or dead-letter ha
SkillScore73Maintained
Automatic
◆Coding pack
Last verified 8/20/2026
What it changes
Passed 13 of 18 test cases with the skill, and 12 of 18 without it.
Without skill68%
With skill73%
Checks it passed that the model alone missed
Declares reactive wrapper type `Publisher<RecordMetadata>` as return type.
1 fixed15 passed either way6 still failing0 broke
Pass-rate lift
+5 pp
Tokens
-17%
Agent turns
0%
Response time
-39%
Model gemini-3.6-flashMeasured 8/20/2026v116 of 22 cases passed with skill · 18 comparable
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
We are writing a high-throughput reactive producer in Micronaut Kafka using RxJava3 or Reactor. Instead of returning `RecordMetadata` directly (blocking), what reactive return type should a `@KafkaClient` method return to emit published metadata asynchronously?
What was checked, without and with the skill
Checked
Without skill
With skill
Declares reactive wrapper type `Publisher<RecordMetadata>` as return type.
Missed
Passed
Ensures return type is non-blocking.
Passed
Passed
case-17 · 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.md42 lines2 files
Micronaut — Kafka messaging
Apply Micronaut Kafka guidance with concrete examples for design, implementation, and error handling.
Constraints
Compile before messaging refactors; verify after changes.
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 Kafka in Micronaut
Review Micronaut Kafka consumers/producers
Improve retries, dead-letter handling, or idempotency in Micronaut Kafka
Configure Micronaut Kafka clients listeners or SerDes
Add Micronaut Kafka retry or dead-letter handling
Workflow
Read reference and assess project context
Read references/514-frameworks-micronaut-kafka.md and inspect current messaging setup before proposing changes.
Gather scope and decide target improvements
Identify delivery guarantees and resilience requirements to define safe improvements.
Apply framework-aligned changes
Implement/refactor clients, listeners, and failure strategies in Micronaut Kafka.
Run verification and report results
Execute build/tests and summarize what changed, what was verified, and follow-up actions.
Use when you need to write unit tests for Micronaut applications — Mockito-first with @ExtendWith(MockitoExtension.class), @MicronautTest with @MockBean, HttpClient @Client(/) assertions, @Property overrides, @ParameterizedTest, and *Test vs *IT naming. For framework-agnostic Java use @131-java-testing-unit-testing. This should trigger for requests such as Add or improve unit tests in a Micronaut project; Reduce unnecessary @MicronautTest usage with Mockito-first tests; Write Mockito-first unit