Winning the Best Design Award at VIBE25-5, an OpenAI-supported hackathon
November 12, 2025
On November 12, 2025, I took part in VIBE25-5: Welcome to San Fransokyo, a hackathon held at Digital Garage in Shibuya, Tokyo. DigitalCrew, the product my team built, won the Best Design Award.
The hackathon
The event was supported by OpenAI and co-hosted by Digital Garage (Open Network Lab and DG Incubation). It brought Y Combinator startups and Japanese student developers into the same room, with one rule: build something in four hours and demo it the same night.
The theme was Y Combinator’s Request for Startups, the list of areas YC wants to fund. The judges were founders of YC companies, including CrustData (YC F24), Dedalus Labs (YC S25), Outerport (YC S24), Random Labs (YC S24) and Lingo.dev (YC F24).
What we built
DigitalCrew is a set of AI agents that build themselves. Describe your company in plain words or upload a document, and it finds where the work is wasted, then creates agents to fix it on the spot.
It does not pick from a fixed catalog; the model designs agents for that one company every time. Enter “a Tokyo delivery company with five trucks,” and it proposes an agent that plans delivery routes and another that handles dispatch, along with an estimate of how fuel costs and workload would change before and after. Company data comes from the CrustData API — CrustData was also one of the judges.
Building it in four hours
After registration and team formation, we had about three hours of actual building time. The front end uses React, TypeScript, Tailwind and shadcn/ui, the back end is Python with FastAPI, and the part that designs the agents runs on OpenAI’s GPT-4. The interface works in both English and Japanese so it can be shown to Japanese companies as is.
Instead of long paragraphs, each proposed agent comes back as a card, so you can see at a glance what each agent does and how much it helps.
The Best Design Award
Besides first through third place, there were three special awards — for design, technical achievement and venture potential — and DigitalCrew received the design award.
At a hackathon about getting something working in a few hours, it was great to be recognized for how we presented it. Because it is hard to see what an agent is doing inside, the way you show it on screen is what makes it understandable. This award reminded me of that.
Event page: VIBE25-5: Welcome to San Fransokyo