Agent-Skills.md

Agent Skills: SOLID Java - Modular Architecture

SOLID principles for Java 21+. Files < 100 lines, interfaces separated, modular architecture. Modules MANDATORY.

UncategorizedID: fusengine/agents/solid-java

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fusengine/agents
fusengineLicense: MIT
7

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pnpm dlx add-skill https://github.com/fusengine/agents/tree/HEAD/plugins/solid/skills/solid-java

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plugins/solid/skills/solid-java/SKILL.md

Skill Metadata

Name
solid-java
Description
"Use when writing or refactoring Java code, structuring modules/[feature]/ layers, or defining interfaces/ contracts (SOLID, files within FUSE_SOLID_MAX_LINES)."
<objective> SOLID Java enforces a modular architecture for Java 25+ (current LTS): every feature lives under `modules/[feature]/` (controllers, services, repositories, interfaces, models/DTOs) with shared code in `modules/core/`, interfaces live only in `modules/[feature]/interfaces/`, controllers stay thin and delegate to services, with files within `FUSE_SOLID_MAX_LINES`, records are used for DTOs and sealed types for restricted hierarchies, and every public method carries Javadoc.

Before writing any new code it requires a DRY check against modules/core/services and modules/core/interfaces. See solid-principles.md for the overview, the per-principle references for SRP/OCP/LSP/ISP/DIP detail, and the templates for module/service/interface/repository/error/test scaffolding. </objective>

SOLID Java - Modular Architecture

Agent Workflow (MANDATORY)

Before ANY implementation, spawn 3 agents in parallel, one Agent call each with a name:

  1. fuse-ai-pilot:explore-codebase - Analyze existing architecture
  2. fuse-ai-pilot:research-expert - Verify Java docs via Context7
  3. fuse-ai-pilot:sniper - Post-implementation validation

DRY - Reuse Before Creating (MANDATORY)

Before writing ANY new code:

  1. Grep the codebase for similar interfaces, services, or logic
  2. Check shared locations: modules/core/services/, modules/core/interfaces/
  3. If similar code exists -> extend/reuse instead of duplicate
  4. If code will be used by 2+ features -> create it in modules/core/

Architecture (Modules MANDATORY)

| Layer | Location | |-------|----------| | Controllers | modules/[feature]/controllers/ | | Services | modules/[feature]/services/ | | Repositories | modules/[feature]/repositories/ | | Interfaces | modules/[feature]/interfaces/ | | Models/DTOs | modules/[feature]/models/ | | Shared | modules/core/{services,interfaces,models}/ |

NEVER use flat src/ structure - always modules/[feature]/

Critical Rules (MANDATORY)

| Rule | Value | |------|-------| | File limit | FUSE_SOLID_MAX_LINES | | Controllers | Thin, delegate to services | | Interfaces | modules/[feature]/interfaces/ ONLY | | Javadoc | Every public method documented | | Records | Use for DTOs (Java 16+) | | Sealed | Use for restricted hierarchies (Java 17+) |

Reference Guide

Concepts

| Topic | Reference | When to consult | |-------|-----------|-----------------| | SOLID Overview | solid-principles.md | Quick reference | | SRP | single-responsibility.md | Fat classes | | OCP | open-closed.md | Adding providers | | LSP | liskov-substitution.md | Contracts | | ISP | interface-segregation.md | Fat interfaces | | DIP | dependency-inversion.md | Injection | | Architecture | architecture-patterns.md | Modular patterns |

Templates

| Template | When to use | |----------|-------------| | module.md | Feature module structure | | service.md | Business logic service | | interface.md | Contract definition | | repository.md | Data access layer | | error.md | Custom exceptions | | test.md | Unit tests with mocks |

Forbidden

| Anti-Pattern | Fix | |--------------|-----| | Files over FUSE_SOLID_MAX_LINES | Split by responsibility | | Interfaces in impl files | Move to interfaces/ directory | | new ConcreteClass() in services | Use dependency injection | | Flat src/ structure | Use modules/[feature]/ | | God classes | Split by responsibility |