Co-founder here. Want to add some context on a decision the article doesn't cover: why Slack.
We tested two surfaces early on - a standalone web app and Slack. The web app: clean UI, full control over the experience. But a lot of friction - why open a browser if you can speak to Viktor in the way you speak to your team? Also, in the webapps, users are used to immediate answers. And Viktor needs time to think/work - like your coworker. In slack we're used to longer wait times. In the end - we speak to humans.
Slack won because it's where work already happens. The agent reads the same channels your team does (crucial for the magical moments!), responds in threads, reacts to messages. There's no context switch. When someone asks the agent to "check what John said about the Q3 budget," it can actually go look - because it's already in the channel where John said it.
The tradeoff is real though. You inherit every Slack UX limitation. You can't build custom UI components. Your entire interaction model is text, threads, buttons, and emoji. We've had to get creative - approval workflows through button clicks, rich output through uploaded files, progress updates through emoji reactions. It's constraining, but the constraint forces simplicity that users actually prefer.
The other thing I'd highlight: the skill system is a compounding moat we didn't fully appreciate at first. Every time any user on a team corrects the agent or teaches it something, that knowledge persists for everyone. Six months in, a team's Viktor knows their project IDs, their naming conventions, which endpoints are broken, who prefers what format. A new hire gets the benefit of all that accumulated context on day one. That's not something you get from a chatbot with a system prompt.