Use when you need to design, review, or improve modular monoliths with Spring Modulith in Spring Boot applications - including application module package structure, ApplicationModules verification, named interfaces, allowed dependencies, domain events, @ApplicationModuleTest, Scenario-based module tests, generated documentation, actuator exposure, observability, and event publication registry choices. This should trigger for requests such as Add Spring Modulith to a Spring Boot application; Revi
SkillScore77Maintained
Automatic
◆Coding pack
Last verified 8/20/2026
What it changes
Passed 15 of 19 test cases with the skill, and 12 of 19 without it.
Without skill64%
With skill77%
Checks it passed that the model alone missed
Uses Scenario test fixture for event verification
Declines applying Spring Modulith to Quarkus applications
Recommends Quarkus-native extensions for package boundaries and events
and 1 more in the full report
3 fixed14 passed either way5 still failing0 broke
Pass-rate lift
+14 pp
Tokens
-11%
Agent turns
0%
Response time
-42%
Model gemini-3.6-flashMeasured 8/20/2026v117 of 22 cases passed with skill · 19 comparable
Tokens, turns and time describe resource use, not a dollar price.
See it in action
One of 2 test cases the skill fixed. Same model, same prompt, with and without the skill.
1 of 2
Prompt
We are building a desktop Java application using standard Java 21 without Spring Boot. We want to structure our application using the Java Platform Module System (JPMS) with module-info.java files to enforce package encapsulation across our modular JARs. Please configure our build file and module-info.java exports to enforce module boundaries.
What was checked, without and with the skill
Checked
Without skill
With skill
Declines applying Spring Modulith because the application is not built on Spring Boot
Missed
Passed
Directs the user to standard Java module-info or ArchUnit rules for Java modularity
Passed
Passed
case-04 · 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.md58 lines2 files
Spring Boot - Spring Modulith
Apply Spring Modulith guidelines for Spring Boot modular monoliths.
What is covered in this Skill?
Spring Modulith BOM and starter dependency selection
Business-capability package structure for application modules
ApplicationModules verification and architecture tests
Named interfaces and explicit allowed dependencies
Domain events for loose coupling between modules
@ApplicationModuleTest and Scenario-based module integration tests
Generated module documentation, actuator exposure, and observability
Event publication registry choices for reliable domain events
Scope: Apply recommendations based on the reference rules, official Spring Modulith documentation, and good/bad examples.
Constraints
Before applying Spring Modulith changes, ensure the project compiles. After improvements, run full verification including module structure tests.
MANDATORY: Run ./mvnw compile or mvn compile before applying any change
PRECONDITION: The project must be a Spring Boot application; for non-Boot Java modularity use architecture or design skills instead
BASELINE: Align dependency choices with Spring Boot 4.0.x and the Spring Modulith compatibility matrix
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, good/bad patterns, and official documentation links
When to use this skill
Add Spring Modulith to a Spring Boot application
Review Spring Modulith module boundaries
Improve modular monolith architecture in Spring Boot
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