mcpbeat

Ios Simulator Browser

openai/ios-simulator-browser

Mirror an iOS Simulator into the Codex in-app browser and render SwiftUI previews from importable Swift packages in that simulator with hot reload. Use when a user wants to watch or interact with an iOS app in the browser, see a SwiftUI preview outside Xcode Canvas, iterate live on a preview, or capture browser-visible simulator proof.

18k tokens
context cost
the whole folder, loaded on every use
7
files
ships runnable scripts
0
copies elsewhere
how many repositories repackaged it
4915
stars on the repo
on the repository, not the skill itself

Install

one command, takes just this skill from the repository
npx skills add https://github.com/openai/plugins --skill ios-simulator-browser

What comes with it

67 163 bytes besides the instruction
agents/openai.yaml
scripts/lib/xcode-project.mjs
scripts/swiftui-preview-browser.mjs
scripts/templates/FocusedPreviewApp.swift
scripts/templates/FocusedPreviewHotReloadRuntime.swift
scripts/templates/PreviewBrowserEntries.swift

The instruction itself

5 sections, as written by the author

iOS Simulator Browser

Browser Workflow

  • Obtain an explicit Simulator UDID from the existing iOS build/run workflow or from xcrun simctl list devices available.
  • Start serve-sim in a long-running terminal pinned to that simulator. Clean up any tracked stale helper for this simulator before starting, and install a trap so the helper is cleaned up when this terminal exits:
   SIM="<simulator-udid>"
   cleanup_serve_sim() {
     npx --yes serve-sim@latest --kill "$SIM" >/dev/null 2>&1 || true
   }
   trap cleanup_serve_sim EXIT INT TERM HUP
   cleanup_serve_sim
   npx --yes serve-sim@latest "$SIM"
  • Open the exact local preview URL printed by serve-sim in the Codex in-app browser.
  • Verify that a real frame is rendering before reporting success. A loaded page alone is not proof that the simulator stream is healthy.
  • Keep the terminal alive while the browser mirror is in use. When finished, stop the terminal and wait for it to exit so the trap runs.
  • If the terminal disappeared or did not exit cleanly, run npx --yes serve-sim@latest --kill "$SIM" before starting another mirror for that simulator.
  • Never run an unscoped serve-sim --kill; another thread may own a different simulator mirror.

SwiftUI Preview Workflow

Use the bundled launcher when the requested previews live in an importable Swift package. Point it at the package manifest and select the target whose previews should be displayed. It generates a disposable host project outside the user's source tree, installs and launches that host in Simulator, and watches the package for edits.

node <skill-root>/scripts/swiftui-preview-browser.mjs \
  /absolute/path/to/Package.swift \
  --package-target "<target>" \
  --device "<simulator-udid>"
  • Watch mode is enabled by default. On a Swift package source edit, the launcher rebuilds a generated dylib and hot-swaps it into the running host without relaunching the app.
  • The generated host shows every preview variant discovered in the selected Swift Package target with in-simulator page controls. To show a subset instead, pass --preview-filter <regex[, ...]>; it matches display names and code identifiers such as StatusRowView_Previews.
  • Once the launcher prints the selected Simulator UDID, start serve-sim for that same UDID and open its printed URL in the in-app browser.

Support Boundary

  • Support Swift Package-backed PreviewProvider and #Preview declarations through the generated host.
  • Do not edit the user's .xcodeproj, .xcworkspace, Package.swift, schemes, or build settings to force preview support.

Proof

For browser or preview QA, capture a browser screenshot showing the simulator frame. For hot reload QA, also report the launcher's hot reloaded package preview ... in pid ... output and show the changed frame after editing.

How to use it

Copy the folder

Take openai/ios-simulator-browser from the repository into ~/.claude/skills for personal use, or into .claude/skills inside a project.

Check the name does not clash

The agent identifies a skill by the name field in its header. Two skills with the same name cannot sit side by side — one of them will be ignored.

Install what it needs

The instructions reference npx. Without those the skill loads but fails at the first command.