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Agent skill

Hexagonal Architecture Layers Java

by Gentleman-Programming in Gentleman-Programming/Gentleman-Skills

Hexagonal architecture layering for Java services with strict boundaries.

MITAuto-check passedDevelopment

Install Hexagonal Architecture Layers Java

skills CLI
$ npx skills add Gentleman-Programming/Gentleman-Skills --skill hexagonal-architecture-layers-java -a claude-code

Project install by default; add -g for ~/.claude/skills/.

GitHub CLI
$ gh skill install Gentleman-Programming/Gentleman-Skills hexagonal-architecture-layers-java --agent claude-code

Project scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).

Manual copy
$ git clone --depth 1 https://github.com/Gentleman-Programming/Gentleman-Skills.git skills-src && mkdir -p .claude/skills && cp -r skills-src/community/hexagonal-architecture-layers-java .claude/skills/hexagonal-architecture-layers-java && rm -rf skills-src

Use ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.

Claude Code skills documentation · loads skills from .claude/skills/

Facts

Skill name
hexagonal-architecture-layers-java
GitHub stars
657
Token cost
~1k tokens
SKILL.md length
163 words
Files
1
Skills in repo
23
Repo updated
First seen
Licence
MIT

At a glance

Hexagonal architecture layering for Java services with strict boundaries.

  • Tasks that involve Design patterns
  • SKILL.md covers When to Use, Critical Patterns, Code Examples and Anti-Patterns, plus 2 more sections
  • Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md
  • Tasks that involve Refactoring

What it does

Hexagonal Architecture Layers Java is an agent skill from Gentleman-Programming/Gentleman-Skills. Hexagonal architecture layering for Java services with strict boundaries. Trigger: When structuring Java apps by Domain/Application/Infrastructure, or refactoring toward clean architecture.

Its SKILL.md is about 1k tokens, which your agent loads only when the skill is triggered. It is a single SKILL.md file with no bundled scripts.

It sits in Development, covering Design patterns and Refactoring. It works with Java. The repository describes itself as: Community-driven AI agent skills for Claude Code, OpenCode, and other AI assistants. Curated patterns and community contributions. The licence is MIT.

When your agent uses it

  • Tasks that involve Design patterns
  • Tasks that involve Refactoring

Example prompts

  • “/hexagonal-architecture-layers-java”

What it can do on your machine

Read from SKILL.md and the folder at commit c8036a3. It shows what the files ask for, not the result of running them.

  • Tool permissions

    Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.

    From allowed-tools in the SKILL.md frontmatter.

  • Runs code

    No scripts in the folder and no shell commands in SKILL.md (its code samples are java).

    From the folder's file list and the shell code blocks in SKILL.md.

  • Network

    Links to these hosts (documentation or services it may open):

    • alistair.cockburn.us
    • oreilly.com

    From URLs in SKILL.md, links to its own repository left out.

  • Credentials

    Names no API keys, tokens, secrets or passwords.

    From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Hexagonal Architecture Layers Java loads about 1k tokens when it runs. Until then it costs about 56 tokens; SKILL.md has 163 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it
~56
When it runs · the whole SKILL.md, loaded when a task matches
~1k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Auto-check passed

The automated check found no risky patterns in SKILL.md.

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from Gentleman-Programming/Gentleman-Skills at commit c8036a3, republished under its MIT licence (© Gentleman-Programming). 163 words, ~1,004 tokens.

Download SKILL.mdSave it as .claude/skills/hexagonal-architecture-layers-java/SKILL.md (or your agent's skills folder).
name
hexagonal-architecture-layers-java
description
Hexagonal architecture layering for Java services with strict boundaries. Trigger: When structuring Java apps by Domain/Application/Infrastructure, or refactoring toward clean architecture.
metadata.author
diegnghrmr
metadata.version
1.0

When to Use

Load this skill when:

  • Designing a new Java service with clean, testable layers
  • Refactoring Spring code to isolate the domain from frameworks
  • Supporting multiple adapters (REST + messaging, JPA + Mongo)
  • Enforcing dependency direction and clear module boundaries

Critical Patterns

Pattern 1: Domain is pure

Domain has no framework annotations, no persistence concerns, and no I/O.

Pattern 2: Application orchestrates

Application defines use cases and ports, calling domain logic and delegating I/O to ports.

Pattern 3: Infrastructure adapts

Infrastructure implements ports and wires adapters (controllers, repositories, clients).

Code Examples

Example 1: Domain model + output port
java
package com.acme.order.domain;

public record OrderId(String value) { }

public final class Order {
  private final OrderId id;
  private final Money total;

  public Order(OrderId id, Money total) {
    this.id = id;
    this.total = total;
  }

  public OrderId id() { return id; }
  public Money total() { return total; }
}
java
package com.acme.order.application.port;

import com.acme.order.domain.Order;
import com.acme.order.domain.OrderId;

public interface OrderRepositoryPort {
  OrderId nextId();
  void save(Order order);
}
Example 2: Application use case + input port
java
package com.acme.order.application.usecase;

import com.acme.order.application.port.OrderRepositoryPort;
import com.acme.order.domain.Order;
import com.acme.order.domain.OrderId;
import com.acme.order.domain.Money;

public interface PlaceOrderUseCase {
  OrderId place(Money total);
}

public final class PlaceOrderService implements PlaceOrderUseCase {
  private final OrderRepositoryPort repository;

  public PlaceOrderService(OrderRepositoryPort repository) {
    this.repository = repository;
  }

  @Override
  public OrderId place(Money total) {
    OrderId id = repository.nextId();
    Order order = new Order(id, total);
    repository.save(order);
    return id;
  }
}
Example 3: Infrastructure adapter + wiring
java
package com.acme.order.infrastructure.persistence;

import com.acme.order.application.port.OrderRepositoryPort;
import com.acme.order.domain.Order;
import com.acme.order.domain.OrderId;
import org.springframework.stereotype.Repository;

@Repository
public final class OrderJpaAdapter implements OrderRepositoryPort {
  private final SpringOrderRepository repository;
  private final OrderMapper mapper;

  public OrderJpaAdapter(SpringOrderRepository repository, OrderMapper mapper) {
    this.repository = repository;
    this.mapper = mapper;
  }

  @Override
  public OrderId nextId() {
    return new OrderId(java.util.UUID.randomUUID().toString());
  }

  @Override
  public void save(Order order) {
    repository.save(mapper.toEntity(order));
  }
}

Anti-Patterns

Don't: Put framework annotations in domain
java
// BAD: domain tied to JPA
@jakarta.persistence.Entity
public class Order {
  @jakarta.persistence.Id
  private String id;
}
Don't: Call infrastructure directly from domain
java
// BAD: domain depends on Spring repository
public class Order {
  private final SpringOrderRepository repository;
}

Quick Reference

TaskPattern
Persist domain dataDefine output port in application, implement in infrastructure
Expose use caseDefine input port and service in application
Keep domain pureNo annotations, no I/O, no framework imports

Resources

© Gentleman-Programming, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

Just SKILL.md in community/hexagonal-architecture-layers-java of Gentleman-Programming/Gentleman-Skills.

Open the folder on GitHubat commit c8036a3

Compare with similar skills

Hexagonal Architecture Layers Java next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.

Hexagonal Architecture Layers Java compared with similar skills
SkillStarsUsed inTokensAuto-checkLicenceRepo updated
Hexagonal Architecture Layers Java this skillGentleman-Programming/Gentleman-Skills657—~1kAutomated safety check: PassMIT
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Swiftui View RefactorDimillian/Skills4k5 repos~2kAutomated safety check: PassMIT
RTK Rust Design Patternsrtk-ai/rtk83k—~1.9kAutomated safety check: PassApache-2.0
Architecture PatternsKartikLabhshetwar/better-shot2.4k2 repos~1.4kAutomated safety check: PassCustom licence
AST Visitor Pattern for Unionsprisma/orm48k—~830Automated safety check: PassApache-2.0

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Works with

Categories

Questions about Hexagonal Architecture Layers Java

What does Hexagonal Architecture Layers Java do?

Hexagonal architecture layering for Java services with strict boundaries. Hexagonal Architecture Layers Java is an agent skill from Gentleman-Programming/Gentleman-Skills. Hexagonal architecture layering for Java services with strict boundaries.

When should I use Hexagonal Architecture Layers Java?

Hexagonal Architecture Layers Java fits situations like: tasks that involve Design patterns; tasks that involve Refactoring.

How do I install Hexagonal Architecture Layers Java in Claude Code?

Run `npx skills add Gentleman-Programming/Gentleman-Skills --skill hexagonal-architecture-layers-java -a claude-code`. Or copy the skill folder (community/hexagonal-architecture-layers-java in Gentleman-Programming/Gentleman-Skills) into .claude/skills/hexagonal-architecture-layers-java in your project. Claude Code loads it when a task matches its description.

How do I install Hexagonal Architecture Layers Java in Codex?

Run `npx skills add Gentleman-Programming/Gentleman-Skills --skill hexagonal-architecture-layers-java -a codex`. Or copy the skill folder (community/hexagonal-architecture-layers-java in Gentleman-Programming/Gentleman-Skills) into .agents/skills/hexagonal-architecture-layers-java in your project. Codex loads it when a task matches its description.

Can I use Hexagonal Architecture Layers Java in Cursor, Gemini CLI or GitHub Copilot?

Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add Gentleman-Programming/Gentleman-Skills --skill hexagonal-architecture-layers-java -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/hexagonal-architecture-layers-java, .gemini/skills/hexagonal-architecture-layers-java, .github/skills/hexagonal-architecture-layers-java and .opencode/skills/hexagonal-architecture-layers-java in your project.

What does Hexagonal Architecture Layers Java need to run?

SKILL.md names no scripts, command-line tools or credentials: Hexagonal Architecture Layers Java is instructions for the agent only.

Does Hexagonal Architecture Layers Java access the network?

SKILL.md names 2 domains. As links in the text: alistair.cockburn.us and oreilly.com. This is read from the text; nothing was executed.

Is Hexagonal Architecture Layers Java safe to install?

Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.

What licence does Hexagonal Architecture Layers Java use?

Hexagonal Architecture Layers Java is published under the MIT licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.

How many tokens does Hexagonal Architecture Layers Java use?

About 1k tokens (SKILL.md is roughly 4k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.

What are the alternatives to Hexagonal Architecture Layers Java?

Skills that share tags, products or a category with Hexagonal Architecture Layers Java: Java Design Patterns Reference (decebals/claude-code-java, 750 stars), Swiftui View Refactor (Dimillian/Skills, 4k stars), RTK Rust Design Patterns (rtk-ai/rtk, 83k stars) and Architecture Patterns (KartikLabhshetwar/better-shot, 2.4k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains Hexagonal Architecture Layers Java?

Gentleman-Programming (a GitHub organization) maintains it in Gentleman-Programming/Gentleman-Skills, which has 657 GitHub stars. The repository holds 23 skills in this directory. The repository was last updated on March 28, 2026.

Source: Gentleman-Programming/Gentleman-Skills on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.