Build mode is for designing the app: data structure, tools, pages, roles, automations. Larger changes usually go through a plan you approve before the AI does the heavy work.Chat mode (including portal chat) is for using the app. The AI only uses capabilities that already exist. Most pages behave like normal software and do not call the AI on every view.If you need something new while testing in Chat, switch to Build mode to add it. Your end users should not be able to redesign the app from the portal.