# Writing

Essays and tutorials by Guilherme Andrade: AI-driven development, Ruby on Rails, architecture. Newest first.

- [Guardrails first: how I make AI do the right job, fast](https://guilherme-andrade.com/writing/guardrails-first.md) (2026-11-03, Essay): From Claude config files to OpenSpec to custom lint rules and dependency checks: how I moved the rules for AI agents from prose the model…
- [Home automation got cheap: Home Assistant on a Pi with Claude](https://guilherme-andrade.com/writing/home-automation-got-cheap.md) (2026-11-03, Essay): Why home automation now costs a fraction of what it used to, how to keep a Home Assistant setup on a Raspberry Pi secure, and what you can…
- [Building 3D models in SketchUp with Claude Code](https://guilherme-andrade.com/writing/sketchup-with-claude-code.md) (2026-11-03, Essay): How I modelled a house renovation in SketchUp without knowing SketchUp: a parametric Ruby model driven by Claude Code, about 34 versions in…
- [tailwindcss-rb alpha released](https://guilherme-andrade.com/writing/tailwindcss-rb-alpha-released.md) (2024-11-02, News): Tailwindcss-rb is as a (sort of) simple Ruby gem that aims to bring Tailwind CSS writing into a more Ruby-friendly environment.
- [What the Rails documentation doesn't tell you: three developer challenges](https://guilherme-andrade.com/writing/what-rails-documentation-doesnt-tell-you.md) (2024-11-02, Tutorial): As a Rails app grows, the documentation stops having answers.
- [Mastering data mapping in Rails with dry-transformer](https://guilherme-andrade.com/writing/mastering-data-mapping-in-ruby-on-rails-with-dry-transformer.md) (2024-04-25, Tutorial): Data mapping is a crucial aspect of Ruby on Rails development, allowing developers to transform and manipulate data seamlessly across…
- [Better data validation in Rails with custom types and dry-validation](https://guilherme-andrade.com/writing/enhancing-data-validation-in-ruby-on-rails-with-custom-types-and-dry-validation.md) (2024-04-25, Tutorial): In the realm of Ruby on Rails development, data validation plays a critical role in ensuring the integrity and reliability of applications.
- [Decimal precision issues in PostgreSQL with ActiveRecord](https://guilherme-andrade.com/writing/precision-issues-in-postgres-activerecord.md) (2024-04-25, Essay): When dealing with financial data or any numeric values requiring precise calculations, developers often encounter challenges related to…
- [The problem with MVC frameworks](https://guilherme-andrade.com/writing/the-problem-with-mvc-frameworks.md) (2023-11-15, Essay): Join me as I dive into the hidden complexities of Ruby on Rails, where its celebrated simplicity meets challenging realities as our…