swiftui-preview

A Claude Code mod that shows SwiftUI previews right in the terminal, rendered by Xcode itself.

Claude calls Xcode's RenderPreview MCP tool on a #Preview; the mod shows the snapshot in a SwiftUI Preview pane — components 1:1 in points like Xcode's canvas at 100%, whole screens fit to the pane. Variants (dark mode, Dynamic Type, orientation), localizations and #Preview(arguments:) come from RenderPreview itself.

Requirements

• macOS with Xcode 27, MCP on: Settings › Intelligence › Model Context Protocol › "Allow External Agents to Use Xcode Tools" = Always (or sudo xcrun mcp-server enable)
• The project open in Xcode
• A terminal that draws images (Ghostty, kitty)

Install

claude mcp add xcode -s user -- xcrun mcpbridge

then, at a Claude Code prompt:

/plugin install swiftui-preview --marketplace degterev/swiftui-preview-mod

Answer y to add the marketplace, then pick a scope.

Use

Ask Claude in plain words; if the file has no #Preview, Claude adds one.

• "show SettingsView"
• "preview the badge in dark mode at AX 3"
• "show ProfileView in Ukrainian, landscape"

The pane opens with each render, labelled with the preview, device and variant (Settings · iPhone 18 Pro · Dark Appearance). When the terminal is too narrow to place it, a toast says so; /swiftui-preview reopens the pane with the last render.

Zoom

[ − ] [ 100% ] [ + ] beside the label zoom from 50% to 400%; click the percentage to reset. With the pane focused (click it), i zooms in, o out, 0 resets. Zoomed in, the picture can outgrow the pane's height, which scrolls, but never its width. The terminal passes no pinch to apps, so a trackpad scrolls the pane but does not zoom it.

How it sizes the picture

• The terminal's cell size is measured, so a component takes its real size in points.
• Components are never enlarged; whole-device screens fit the pane's height.
• The snapshot is padded to the pane's cell grid, so it is never stretched.

Limitations

• Assumes a Retina (2x) display: on a 1x monitor components show twice their size.
• Xcode caps a snapshot's long side at 1500 px, so a whole screen in a very tall pane is slightly soft.
• Only the last render is kept.
• No horizontal panning: a whole screen zoomed past the pane's width stays at that width.

Development

claude plugin validate .
claude plugin test .

License

MIT