Introducing Type Guard to Steep

February 2, 2026

Type Narrowing for Real-World Ruby Applications

Based on the RubyKaigi 2025 talk “Introducing Type Guard to Steep” by Takeshi Komiya CTO at Time Intermedia Inc., maintainer of rbs_rails and Rails type generators. Presented at RubyKaigi 2025.

Context and Attribution

This article is a technical analysis and expansion of the RubyKaigi 2025 conference talk “ Introducing Type Guard to Steep ”, presented by Takeshi Komiya (@tk0miya), a core contributor to the Ruby typing ecosystem and one of the maintainers of rbs_rails.

The original talk introduces Type Guard , a set of enhancements to Steep aimed at improving type narrowing in real-world Ruby and Rails applications. What follows is a deeper, written exploration of those ideas, with additional explanations and practical framing for production Ruby codebases.

👉 Read the full article.

https://rubystacknews.com/2026/02/02/introducing-type-guard-to-steep/