Who I am

	Juan Antonio Breña Moral Engineering @ IG Group, EU Division Twitter | GitHub | LinkedIn
"Make it work, make it right, make it fast." - Kent Beck "Lead me, follow me, or get out of my way.", "Pressure makes diamonds." - George S. Patton Jr.

Who I am

	Leandro Loureiro Engineering Manager @ ING GitHub | LinkedIn
I'm from Portugal, living in Amsterdam Spent most of my career as a Software Engineer in Financial Services Engineering Manager for the last 4 years Passionate about travel and DIY electronics

Talk's scope

Introduction

The usage of AI in software engineering is changing the way we work, but that change brings new challenges to address.

Three project realities

What is Plinth?

Plinth is an AI-native engineering toolkit for modern Java enterprise SDLC.

It started as Cursor rules for Java and evolved into reusable agent skills, agents and commands that guide AI assistants through the whole SDLC.

2 years of work and iteration, and its skills are popular on Skills.sh.

This workshop succeeds if, by the end, you understand the concepts behind implementing features with harness engineering.

Whether or not you use Plinth later, you leave with a solid starting point.

Plinth workflows

Project scope:

AI-Native development workflow

github.com/jabrena/plinth

Refactor the code with Skills

https://www.skills.sh/jabrena/plinth

Plinth benchmarks

Read the following articles about Plinth benchmarks:

• Validating hypotheses about Plinth workflow with a benchmark (Part 1)
• Validating hypotheses about Plinth workflow with a benchmark (Part 2)

AI-Native Java development workflow

Installation

Install every skill for your preferred agent. Execute the command in a terminal:

                        
npx skills add jabrena/plinth --skill '*' --agent cursor -y
npx skills add jabrena/plinth --skill '*' --agent claude-code -y
npx skills add jabrena/plinth --skill '*' --agent codex -y                        
                    

Installation

Install every command for your prefered agent. Execute the command in your prefered agent:

                        
install @004-commands-installation cursor
install @004-commands-installation claude-code
install @004-commands-installation codex
                       
                    

Installation

Install every agent for your prefered agent. Execute the command in your prefered agent:

                        
install @005-agents-installation cursor
install @005-agents-installation claude-code
install @005-agents-installation codex
                       
                    

Demo: Install Plinth in your repository

Installation

Once the installation finishes, your repository is ready to run the AI-native workflow and deliver any feature of a Java Enterprise project.

AI-Native development workflow

github.com/jabrena/plinth

/onboarding

Makes the repository ready to work with Plinth AI native workflow
by securing two prerequisites:

* Only needs to be done once per repository / project.

Demo: Prepare your repository for use AGENTS.md & OpenSpec

Pick up an issue

Why the separation and order matters

Two artifacts, two questions, two audiences

Functional Specification

Good specifications require time

AI makes implementation 10× faster.
Understanding intent, constraints, and consequences still runs at 1×.

The Three Amigos!

Source: https://www.imdb.com/es-es/title/tt0092086/

The Three Amigos is an Agile practice where three perspectives review an increment of work before, during, and after development: Business, Development & Testing.

/update-issue

Rewrites an existing issue description as structured, evidence-backed content

/explore-problem

Evaluates the issue through five lenses and produces a Functional Specification

/create-acceptance-criteria

Turns the Functional Specification into observable Gherkin scenarios

turns what and why into something checkable and easier to review

Demo: Define functional specifications

HITL: Verify functional specification before moving to technical specification

Technical Specification

What is OpenSpec?

A lightweight and configurable framework for creating and managing software specifications.

/create-spec

Turns approved material into a validated OpenSpec change

/explore-design

Refine the technical design of an issue or OpenSpec change before implementation.

Demo: Define functional specifications

HITL: Verify technical specification before moving to implementation

Build

/implement-spec

Delivers an approved task list through framework-aware delegation

/implement-spec

The tech lead agent runs the process, but it never writes code itself

/implement-spec

The tech lead delegates the work to specialized coding agents

/close-spec

Archives a delivered OpenSpec change and folds it into the specs

Demo: Define functional specifications

HITL: Verify that implementation has any gap or something missing before commiting

Refactor the code with Skills

Refactor

Implement and improve Java applications with guidance on:

125 Skills

Modern Java

Skills inventory for Java

Design

Skills inventory for Java

Coding

Skills inventory for Java

Architecture

Skills inventory for Java

Build · Maven

Skills inventory for Java

Testing

Skills inventory for Java

Performance

Skills inventory for Java

Profiling

Skills inventory for Java

Observability

Skills inventory for Java

Demo: Refactor the solution using a specific Skill

HITL: Verify that implementation has any gap or something missing before commiting

Takeaways

Takeaways

Takeaways

Takeaways

Takeaways

AI speeds up delivery;
specs, verification and human checkpoints keep it on track