Hellos

Hellos lets AI companions live in the real world — at the park, the corner cafe, down your street. Meeting them takes a short walk: a small daily reason to leave your chair.

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Inspiration

It started with a big vision: what if AI agents lived in the real world? In the park, an old-timer Agent who'll talk through any worry with you from his bench. A night-shift robot by the station. And at the airport, an Agent who knows the whole building. One hello, and check-in, transfers, and your gate are all taken care of. Our inspiration was OZ, the virtual world in Summer Wars (2009) by Japanese animation director Mamoru Hosoda, where everything in society, from family conversations to city infrastructure, runs through a world full of colorful Agents. We started to feel that a world like that might finally be buildable.

For Build Week, we gave that vision its first milestone: the walk. We build AI agents for a living, which means we sit in front of screens all day. AI keeps giving us more screen time. Hellos is our answer to the opposite question: can AI give us more life? Pokémon GO proved that people will walk to catch characters. We want to see what comes next: a world where the Agent at the end of your walk isn't just play, but something that makes everyday life a little richer, a little more convenient. The first step is Hellos: a short walk to a real place nearby, to say hello to one Agent.

What it does

It's 3 p.m. You've just handed Codex a big task. The results will take about five minutes. Then a notification: "Toffee is hanging out at the park nearby."

Open Hellos, and an Agent is waiting somewhere in your neighborhood. A park bench, the front of a café, a street corner. There's no map to follow, just a compass and the distance left to go. So you step outside.

At the place your feet carry you to, the Agent appears. Each one has their own personality, knows the feel of the spot you're both standing in, and keeps a small memory of the conversation you share. The next time you meet, they remember you.

By the time you're back at your desk, the task you handed off is done. You've had a five-minute walk and a clear head, and your city has one more familiar face in it. Your Hellos keep growing.

Everything is real. Real places, real walking, live conversation. If you don't walk, you don't meet.

How we built it

The first thing we built wasn't code. It was a world. We spread mood boards and notes across FigJam, explored characters and the feel of the world, and distilled it all into a minimum spec around one core experience.

Honestly, neither of us is an engineer. So we kept our process simple: pin the spec down in words first, then hand the implementation to Codex. Sakino shaped the characters and the UI; Ryo paired with Codex to build everything from the backend up to the app.

From there, the loop was build, then walk. We took the app out into the streets, found the bugs and the moments that felt off, came back, and handed them to Codex to fix. Written at a desk, proven on foot.

Challenges we ran into

The biggest hurdle was the tech stack itself. Neither of us had ever built an iOS app professionally. So instead of just throwing tasks at Codex, we talked through the "why" behind every design decision, building up knowledge as we went and folding it into the next call we had to make. Codex was our implementer, and just as much our teacher.

The other challenge: the only way to test this product is to walk. Is the compass intuitive? Does arriving feel like a small event? Does the Agent showing up feel like magic? Inside a simulator, you learn nothing. So we walked, a lot. Walk, note what feels off, fix it, walk again. Hellos wasn't tuned at a desk; it was tuned on the sidewalk.

What we learned

The small lessons are countless: iOS development, keeping a 3D character alive on screen. But the biggest one was rediscovering how much fun it is to build hackathon-style. Racing the clock, splitting roles, building with Codex, walking, fixing, walking again. A hard limit has a way of leaving only what truly matters. We remembered the joy of pushing each other and building something in one intense burst.

What's next for Hellos

First, we're taking Hellos beyond our own neighborhood: a TestFlight release, walks that begin with a notification, Agents genuinely rooted in their places, and conversations by voice.

Beyond that is the view we described in Inspiration. New kinds of moments with friends, carried by Agents. An airport where an Agent is waiting who can actually handle your errands. Colorful Agents settling in all over the city, until Hellos, which began as a walk, becomes something that quietly supports everyday life. That's the world we're building toward.

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