The release of Yadda 3.0.0 marks a significant modernization of the JavaScript Behavior Driven Development (BDD) library, transitioning it to a Node-only architecture. The update removes legacy integrations such as CasperJS, PhantomJS, Bower, and Component, while adopting modern tooling including Biome, lefthook, and node:test. The codebase has been refactored to ES6 syntax, now includes TypeScript definitions, and provides updated examples for Playwright and Puppeteer. Notably, the modernization process was largely executed using Claude Code with the Opus 4.8 model. The author utilized a phased approach—separating the removal of obsolete functionality, toolchain updates, formatting, and source modernization—to maintain strict control over the implementation. By deliberately avoiding simultaneous modifications to production code and tests, the author ensured the existing comprehensive test suite remained a reliable external constraint against agent-driven changes. This process allowed the entire package to be updated and published in approximately one day of elapsed time. Furthermore, the introduction of GitHub-flavored Markdown support in version 3.1.0 allows feature specifications to serve as both human-readable documentation and executable contracts that provide rich domain context for AI agents in automated development pipelines.