If you mostly use chatbots and you’re starting to track new AI tools, this is the mistake that burns time: you see the shiny mockups, assume the value is speed, and miss the file that actually changes your next move.
The product move here isn’t the canvas. It’s google-labs-code / design.md [C001]. My read is simple: DESIGN.md is turning design rules into an asset an agent can reuse [C002].
Why that matters for a normal person: a mockup is one output. A rule file is closer to reusable memory. If the tool can read your style rules, carry them into another app, and keep using them, then the interesting part is no longer “it drew something fast.” The interesting part is “it learned the rules once, and can use them again.”
That is also where the cost of a bad read shows up. If you only watch the surface demo, you can waste time, budget, and attention chasing prettier pictures. The quieter cost is worse: you keep circling the visible feature and miss the step that may actually matter in the next generation of tools.
The evidence is narrow but pointed. Google describes DESIGN.md as an AI-readable plain text file for moving rules between design and coding tools. Then the Stitch SDK exposes two separate actions around that file: one to upload it, and one to turn it into a design system. That makes it look less like a note for humans and more like an input the tool can act on again.
That’s the filter I’d use when a new AI design tool hits your feed: don’t start with the feature list. Start with the rule file. A product update is worth sharing when it changes your next decision, not when it merely adds more surface area.
Scope note: this is based only on Google’s blog post and the Stitch SDK source, not a live team rollout, a production workflow test, or a benchmark.