A developer cycles the chat input with Shift+Tab looking for Design Mode, finds only the other modes, and concludes the feature is missing from their build. What is actually the case?

The principle — Not every Cursor mode is reached the same way. Plan, Ask and Debug rotate in the chat input's mode picker, but Design Mode sits somewhere else entirely, and looking for it in the picker is how people conclude it does not exist for them.

Why the key is correct — Cursor states that Design Mode lives in the browser inside the Agents Window. You open that browser and toggle Design Mode there with Cmd + Shift + D, and the same shortcut turns it off again to return to normal browsing. The placement follows from what the mode does: it directs agents with visual prompts against the running product, letting you click an element, draw over the page or narrate a change by voice. None of those gestures mean anything in a text chat panel with no rendered application in front of it.

Why the others are wrong — Waiting for a development server to unlock a picker entry gets the dependency half right and the location wrong; a running app matters, but the entry is not there to appear. Design Mode has not replaced Ask mode either, since Ask remains the read-only mode for understanding code and the two serve unrelated purposes. And no editor setting adds it to the rotation, because it is an overlay on the browser rather than a mode of the chat panel.

Remember this — If Shift+Tab cannot find Design Mode, stop cycling and open the Agents Window browser.

Sources — Cursor's Design Mode documentation.