Reddit Proto

A design org could imagine faster than it could decide. An idea went through design, a descope, implementation and an experiment, and then it waited. Most ideas waited forever.

So decisions got made on opinion: in a deck, by whoever argued best.

The spark

One feature concept went from idea to full fidelity in 3 days, and leadership could use it, not just look at it. I ran its reviews with the CEO and the CPO.

The pitch

Proto wasn't a faster way to make mockups. It was a way to decide.

Designers vibe-code prototypes on real, logged-in data, so they behave like the product. No more building in production for a quarter to find out.

Policy

An executive brief turned the tool into policy: Proto became the required system for reviewing work with leadership.

A required system is only as good as its front door. I designed it as four steps a designer can do alone, in an hour, without opening a terminal.

The repo is internal, so these are drawings, not screens.

The rollout

Two-thirds of UX onboarded in one week. We went team by team and took blockers out as we found them, like a limit on creating keys.

A reverse show-and-tell had designers showing us what they had built. A month before the July summit, every pod was on track to ship a live URL there in about 75 minutes.

The harness

Underneath is a harness of component specs, interaction patterns and agent guidance: 65 components and 16 agent skills.

It runs on Next.js App Router, TypeScript, React and Tailwind, built with Cursor, with Figma to iOS through MCP.

The engineering is in the documents. A spec only helps an agent if it is specific enough to be wrong.

Not everyone wanted the old process to collapse. Research leadership worried about unmoderated testing, and some engineers felt the tool shrank their craft. I'd bring both groups in as co-owners earlier.

The +80% is engineering's judgment of handoff quality, not a measurement, and should be read as one.

A harness moves work as much as it removes it. Guidance has to be kept current, or the agent builds last quarter's conventions with total confidence.

Proto is now the company's de facto way to decide: how teams get aligned and get to a decision. 100% of UX and Product use it.

130 people have deployed 800 prototypes, and dozens of research studies have run on them, with real insights. Onboarding takes an hour, and handoff quality is up 80%, assessed by engineering.

Leadership gets a link. No deck required. The prototypes get thrown away. The harness stays.