Yadda 3.0.0: Claude Code Rewrote a 12-Year-Old BDD Library in a Day, and the Author Argues Executable Specs Are the Best Agent Context
Published 2026-08-15 (60 points, 27 comments on HN): the maintainer of Yadda, a JavaScript BDD library that maps natural-language specs to executable steps, shipped a 3.0.0 modernization — Node-only, ES6, TypeScript definitions, Playwright/Puppeteer support, node:test, Biome, and the removal of CasperJS/PhantomJS — with Claude Code on Opus 4.8 writing most of it in roughly one day. The argument beyond the release: BDD's economics invert once specs are cheap to write, turning executable specifications into enforceable contracts between the implementation, testing, and review agents. Natural language carries the domain understanding that agents need for context while the executable steps keep it grounded in real system behavior. Version 3.1.0 added GitHub-flavored Markdown so specs can live in project docs.
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