Yadda 3.0 Review: BDD AI Agents and Executable Specifications (2026)
BDD (behavior-driven development) writes requirements in ordinary language and binds each step to real code. Yadda 3.0 matters in 2026 because its author argues executable specifications become more valuable once coding agents write the software: a wiki says what a system was supposed to do; only an executable spec proves what it does. That is the whole thesis in one line, and it is the reason a small, fifteen-year-old JavaScript library got a Hacker News thread, a rewrite by Claude Code, and a place in the spec-driven-development revival of 2026. This review covers what Yadda 3.0 actually is, what changed, how it compares to CucumberJS, what its own AI-assisted build reveals, and where the evidence stops supporting the hype. ...