Guide

Wrong shape is the most expensive UX bug: a full agent UI for a single-field form, or a bare chat box for irreversible account changes. Pick the interaction that matches frequency, stakes and how much autonomy users want.

Concept

Before you start: product strategy decides whether AI belongs at all. This page is the interaction once you have decided to ship.

The big idea

ModelFeels likeBest whenFailure mode
ChatConversation threadOpen-ended tasks, explorationEndless chat as a junk drawer for every feature
Inline assistGhost text or sidebar in the artifactWriting, code, sheets — user stays in flowOver-aggressive suggestions interrupting typing
CopilotSidekick with tools on a canvasMulti-step work with a durable documentOpaque actions the user cannot undo
Autonomous agentGoal in, result outClear goals plus verifiable outcomesSilent wrong side effects
Background automationNo UI until exceptionHigh volume, low ambiguity pipelinesNo path to notice or correct errors

Default to copilot / assist when stakes are high or taste matters (code merge, customer email). Use agents when the task is ambiguous but outcomes are checkable (tests pass, form validates). Use chat when the job really is dialogue — support, tutoring — not as a lazy wrapper around a form.

Many products mix models: chat for discovery, inline edit for the artifact, human approval before irreversible tools.

Walking through a refund

"Design the UX for an agent that can refund customers." Chat alone is the wrong shape. The irreversible action needs a confirmation, an undo window and a visible tool trace. Assist-plus-approval is the product: the model drafts refund $40 on order 1842, the human clicks, the system records who approved.

A single-field "reason for return" form does not need an agent canvas. A million-document extraction pipeline does not need a chat thread. It needs a batch job plus an exception queue.

Common mistakes

  • Chat as the default for every feature. Forms stay forms.
  • An agent UI with no review when the outcome is not verifiable.
  • Background automation with no exception path. Errors ship silently.

Check yourself

  1. A user is editing a customer email. Which model? Inline assist or copilot, so they stay in the draft.
  2. Outcomes cannot be checked automatically. What do you require? A human in the loop before side effects.

Key takeaways

  • Match chat, inline, copilot, agent or batch to task structure and stakes.
  • Assist when taste or risk is high. Agents when outcomes are checkable.
  • Mix models in one product. Chat finds; inline edits; a gate sits on writes.
  • Background jobs need an exception queue, not a chat box.

Further learning

Once the shape is right, calibrate what users believe in calibrated trust.