Descriptions:
Web Dev Cody shares a lightweight but effective strategy for preventing AI coding assistants from regressing existing functionality when iterating on complex features. Working on a real video editor project with a timeline component exceeding 3,200 lines of code, he demonstrates how a single markdown requirements file—updated alongside every code change—gives Claude Code and Opus 4.5 a persistent reference that dramatically reduces the chance of breaking something that was working before.
The workflow has two entry points. For a new project, ask the LLM to analyze the existing component and generate a bullet-point requirements file covering all features and edge cases before any modifications begin. For ongoing work, include the requirements file in every coding prompt and explicitly instruct the model to update it when changes are made—keeping the document as the authoritative source of truth for what the component is supposed to do.
Cody also addresses why he avoids full test-driven development for solo prototyping with LLMs: TDD slows iteration significantly, burns extra tokens on test generation and verification passes, and can lead models to modify tests rather than fix broken implementations. The markdown approach keeps velocity high while providing just enough guardrails for complex, interdependent components. He draws a contrast with BMAD and SpecKit, framing those as overkill for rapid prototyping, and notes the technique pairs naturally with screenshot context to help models understand visual components alongside code.
📺 Source: Web Dev Cody · Published December 31, 2025
🏷️ Format: Tutorial Demo
