Yup just another user account. It can work without this as well (we support ingesting other resources such as help center articles, pdfs, etc.) but at that point it's no different from any other (dumb) AI chatbot out there that just spits out a bunch of itemized bullets.
Even with an API spec it wouldn't "just work". You'd still need to handle authentication and have a place to manage which APIs you want the in-app agent to have access to / when to call a given tool.
And believe it or not, even big companies with big eng teams don't have API specs available for their applications ¯\_(ツ)_/¯
We use a browser-based agent to learn all the APIs and turn them into skills. Most users will run this in a staging/test account to create all the recipes/blueprints. Our agent is also instructed to not take any destructive actions - but of course LLMs make mistakes (hence the test account :) ).
Our customers run the training on their own applications using a demo or staging environment. Then they install the in-app agent you see in the demos and turn on the tool calls they like. All the API calls are executed client side and never touches any of our servers.