Agentic UX is the new responsive design

The viewport stopped being the unit

For fifteen years the question was: what does this look like at 1440, at 768, at 375? Responsive design hard-coded that question into our muscles — we shipped a layout for every breakpoint and called it done.

Agentic UX changes the unit. The viewport doesn't define the experience anymore; the intent does. A user typing "summarise this thread" doesn't care if they're on a laptop or a watch. They want the summary surfaced wherever they happen to be looking.

Three patterns I keep re-using

1. Surface anywhere. The agent's output should be renderable as a card, a chat reply, a panel insert, or a notification — same payload, different framing.
2. One verb, one screen. When you do show UI, commit to a single action. The era of dashboards-as-output is fading; the era of next-step-as-output is starting.
3. Conversational fallbacks. If the rendered card can't carry the answer, the agent should know how to talk about it instead.

What it means for portfolios

This is also why I'm sceptical of agentic mockups that look like web pages with a chat sidebar. The most interesting agents I've shipped don't have a "page" at all — they have a posture, a tone, and a handful of places they're allowed to show up. Designing them is closer to designing a colleague than designing a screen.