---
title: "Create UI prototypes using agents in Xcode"
description: "Use Xcode coding agents and previews to prototype SwiftUI screens, realistic states, and tunable interactions without giving up design judgment."
shoutout: "Unofficial, made with love by Superwall - the best way to monetize your apps."
category: "Design"
---

# Create UI prototypes using agents in Xcode


[Watch on Apple Developer](https://developer.apple.com/videos/play/wwdc2026/227/)

Use Xcode coding agents and previews to prototype SwiftUI screens, realistic states, and tunable interactions without giving up design judgment.

## TL;DR

- Use Xcode coding agents as prototyping collaborators: write specific prompts, ask for multiple named Swift previews, compare directions, then remix promising elements.
- Bring prototypes closer to real use by asking agents for plausible sample data, reusable sample models, and previews for edge cases such as empty states, long text, and unbounded lists.
- For interaction design, create custom tuning panels in Xcode previews to adjust animation phases, spring/ease parameters, delays, staggered entrances, layout options, and app states.
- The core guidance is to shorten feedback loops while retaining human judgment; agents can generate real native code, but they should not decide the experience for you.

## Prototype with agents, but keep design judgment human

The session frames prototyping as a way to explore many design ideas quickly before an app's direction hardens. Xcode coding agents can generate native code from a description, while Xcode previews let developers inspect and interact with UI without rebuilding and running the app for every change.

The recommended workflow is collaborative rather than delegating design decisions. Agents are useful for producing starting points, variations, sample content, and tuning utilities, but the developer or designer remains responsible for deciding what serves people best.

- Use coding agents to request code changes or features directly in Xcode conversations.
- Use Xcode previews by ensuring the Swift file has a preview view and opening the canvas.
- Prefer prototyping key screens and moments in real native code so promising work can be carried forward.
- Avoid treating agent output as authoritative; evaluate, revise, and discard aggressively.

## Explore UI possibilities by going wide first

A vague prompt such as asking for a UI for a regularly meeting book club can anchor the prototype on arbitrary layout, navigation, and feature choices. The session's example shows how an agent may invent features such as polling or photo galleries, which can create feature creep and make later refinement harder.

Better prompts are specific about the app's intended features, desired mood, and exploration strategy. The key tactic is to ask for multiple named variations, each with its own Swift preview, so the generated ideas can be compared side by side and referenced in follow-up prompts.

- Define the core features before prompting, rather than letting the agent infer them.
- Include stylistic cues such as atmosphere, color palette, typography, or metaphor.
- Ask for multiple divergent options early, not just one implementation.
- Follow up by naming promising variations and asking the agent to remix specific elements.
- Repeat the cycle: go wide, remix, refine.

### Prompt pattern for UI variation exploration

The session recommends prompts that specify features, stylistic direction, multiple options, and separately named Swift previews.

```text
Create multiple UI variations for a book club app.
Include these specific features: current book, meeting details, discussion, member progress, and prior books.
Explore distinct visual directions, such as warm coffee-shop, editorial typography, and progress/racetrack metaphors.
Give each variation a unique name and its own Swift preview so I can compare them.
```

### Prompt pattern for remixing generated ideas

After reviewing generated directions, reference the named previews and ask the agent to combine only the useful parts.

```text
Create new hybrid iterations using only these elements I liked:
- the clear current-book and meeting section from Cozy
- the pleasing typography from Editorial
- the standings/progress-board idea
- the current book image treatment
Give each iteration a unique name and its own Swift preview.
```

## Make prototypes feel lived in with realistic content and edge cases

Once the structure is promising, agents can help populate prototypes with plausible sample data so the UI can be evaluated before real users have enough personal content in the app. For the book club example, sample discussions, books, members, meeting descriptions, and book covers reveal layout and interaction issues that blank placeholders hide.

The session emphasizes thinking through edge cases yourself and asking for multiple previews that cover them. Agents can help author sample models, but the prompt should make the content relevant to the app's audience and easy to reuse or edit.

- Ask for many previews, not one happy-path state.
- Cover empty states, such as no scheduled meeting or no selected book.
- Stress-test long text, long conversations, many members, many previous books, and other unbounded UI areas.
- Specify whether text should truncate, wrap, or trigger a layout change.
- Ask for sample models in a reusable, readable file so future prototypes can reuse or modify them.
- Use realistic content to identify missing flows such as blank-slate UI, account management, and calls to action.

### Prompt pattern for realistic sample states

The recommended prompt names concrete edge cases, requires reusable sample data, and asks for descriptive previews.

```text
Populate the prototype with plausible book-club sample content and reusable sample models in a separate, easy-to-edit file.
Create multiple named Swift previews for these states:
- active club with current book and meeting
- no meeting scheduled
- long meeting description
- many participants on the leaderboard
- long discussion thread
- empty or first-run state
Keep the sample discussions centered on books and make each preview easy to refer to in follow-up revisions.
```

## Tune key moments with dedicated preview controls

Static layout is only part of the prototype. SwiftUI interactions, animations, transitions, friction, inertia, device-motion responses, and haptics shape how an app feels. The session focuses on animation tuning, especially ease animations and spring animations.

Rather than repeatedly editing scattered constants in code, create a custom tuning panel that exposes the parameters relevant to the interaction. Xcode agents can build these panels, and Xcode previews can display them alongside the UI in a wider canvas so parameters can be changed without context switching.

- Ease animations can tune acceleration, deceleration, and duration.
- Spring animations expose parameters such as stiffness, damping, and mass.
- Break complex animations into named phases so the panel, prompt, and code share a vocabulary.
- Use tuning panels for animation parameters, app states, colors, font styles, visual offsets, and other configuration choices.
- Prefer side-by-side preview layouts over modal or obstructing controls when tuning visual changes.
- Inspect phases independently to diagnose issues such as excessive delay or staggered entrance timing.

### Prompt pattern for an animation tuning panel

The session recommends asking the agent for a purpose-built panel that exposes animation phases and tunable parameters in preview.

```text
Build a tuning panel for this transition and show it side by side with the app UI in a wide Xcode preview.
Break the animation into phases:
1. transition from overview to detail page
2. staggered entrance of subsequent rows
Expose controls for duration, delay, stagger timing, spring/ease style, and any relevant presets such as bouncy.
Let me isolate each phase and replay the transition while adjusting values.
```

## Workflow takeaways

The overall practice is to use Xcode agents to reduce iteration cost, not to replace taste or product thinking. The most productive prompts are explicit, comparative, and structured around feedback loops: generate alternatives, inspect them in previews, identify concrete issues, and ask for targeted revisions.

The session closes by pointing developers to "Xcode, agents, and you" for more on using agents in Xcode.

- Use agents for breadth, sample data, and tooling around iteration.
- Use previews to compare states and interactions quickly.
- Use human judgment to choose the right direction and refine it into a people-centered experience.
- Consult the related session "Xcode, agents, and you" for broader Xcode agent guidance.

## Related Sessions

- [Xcode, agents, and you](https://wwdc.ai/2026/259)

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