Show a live iOS Simulator in the dashboard's Browser side panel while building or testing an iOS app. Use when the user asks to preview an iOS/SwiftUI app, run an app in the simulator, "show me the app", test in the iOS simulator, or watch you drive an iOS app. macOS + Xcode only.
Standardmäßig ist der Prompt ausgewählt, der zuerst die Quelle prüft. Sie können zu einem direkten Befehl wechseln oder eine lokale Kopie herunterladen.
Quelldateien prüfen
Lesen Sie SKILL.md und alle von SkillsMP angezeigten Begleitdateien, bevor Sie sich für eine Installation entscheiden.
Mit Codex oder Claude installieren Kopieren Sie diesen Prompt, fügen Sie ihn in Codex, Claude oder einen anderen Assistant ein und lassen Sie die Skill-Seite prüfen und installieren.
Ein direkter Befehl überspringt den Prüf-Prompt. Prüfen Sie die Quelle, bevor Sie ihn ausführen.
Show a live iOS Simulator in the dashboard's Browser side panel while building or testing an iOS app. Use when the user asks to preview an iOS/SwiftUI app, run an app in the simulator, "show me the app", test in the iOS simulator, or watch you drive an iOS app. macOS + Xcode only.
triggers
ios simulator, iphone simulator, iphone preview, swiftui preview, run in simulator, xcode app preview, mirror simulator, show me the app on iphone
iOS Simulator Preview (Browser-tab mirror)
Mirror a running iOS Simulator into KiroCrew's Browser side panel so the user
watches the app — and you driving it — live next to the chat.
Architecture, end to end, all local: simulator → serve-sim (loopback HTTP)
→ the kirocrew:preview marker → Browser panel iframe. Nothing leaves the
machine. This mirrors OpenAI Codex's ios-simulator-browser approach (same
serve-sim mirror) with one substitution: Codex opens the URL in its in-app
browser via a browser tool, while KiroCrew's panel is driven by the hidden
preview marker (see the web-preview skill).
Requirements
macOS only. Apple's simulator runs nowhere else. On Linux/Windows say so
and stop — do not attempt a fallback.
Xcode with an iOS platform installed, and the license accepted. xcrun simctl list devices must work.
Node/npx. The launcher pins --registry=https://registry.npmjs.org because
a local npm config may default to an authenticated internal registry (which
401s on a public package). The serve-sim version is pinned in the
launcher () rather than floated, so a start never
auto-executes an unreviewed release; bumping it is a deliberate change.
SERVE_SIM_VERSION
First start takes a couple of minutes (npx download + device boot); later
starts are fast.
Call the script by path; do not cd into the skill folder.
KIROCREW_HOME, when set, must be an ABSOLUTE path (~ is fine — the launcher
expands it). The launcher is invoked by path from whatever directory the session
is in, so a relative home would resolve differently per caller and a start
from one project directory would not be visible to a stop from another. The
launcher refuses a relative value with a JSON error rather than splitting state.
Workflow
1. Start the mirror
python3 "$SKILL_DIR/scripts/sim_mirror.py" start
Use the bundled launcher, not a bare npx serve-sim. It handles the parts
that silently break otherwise: detaching the server so it survives your turn
ending (a turn-scoped child gets reaped at turn end), device
selection/creation/boot, scoped stale-mirror cleanup, per-UDID pidfiles, and
refusing any non-loopback URL.
Optional --device "<udid-or-name>" targets a specific simulator (e.g. the one
your xcodebuild destination used). Without it: prefers an already-booted
device, else the newest iPhone, else creates one.
Prints JSON: {"udid", "name", "url", "pid", "log"}.
2. Open it in the Browser panel
Emit the hidden marker in your NEXT message, using the exact url from step 1:
Everything you do shows up live in the user's panel. For your own checks
take simctl screenshots — the mirror is for the user; don't scrape it.
Bound every simctl call with a timeout (e.g. subprocess.run(..., timeout=90)). A wedged CoreSimulator makes simctl block indefinitely, which
otherwise hangs your turn instead of returning a diagnosable error.
4. Stop when done
python3 "$SKILL_DIR/scripts/sim_mirror.py" stop # all tracked mirrors
python3 "$SKILL_DIR/scripts/sim_mirror.py" stop --shutdown-device # also power off
python3 "$SKILL_DIR/scripts/sim_mirror.py" status # pid alive? url?
stop is scoped to this launcher's own pidfiles, and --device here must be a
UDID (not a device name) — it is validated before touching any path or
signaling anything. Never kill serve-sim processes you don't track —
another session may own them.
Failure modes
Each of these was hit in practice; the stated cause is the verified one.
simctl missing → Xcode not installed. Tell the user; stop.
"You have not agreed to the Xcode license agreements" → the user must run
sudo xcodebuild -license accept themselves (needs sudo + an interactive
prompt you cannot drive).
"no available iOS runtimes" → xcodebuild -downloadPlatform iOS
(multi-GB; check free disk first).
simctl hangs, or repeated error encoding frame: encodingFailed →
CoreSimulator version mismatch. An Xcode upgrade while a device was
booted orphans that device: the new framework cannot drive it, so simctl
blocks and the mirror captures nothing while still serving HTTP 200.
Recovery: stop the mirror, pkill -x Simulator, pkill -f CoreSimulator.CoreSimulatorService, pkill -f launchd_sim, then boot a
fresh device. launchctl remove alone is not enough.
Device creation fails "Incompatible device" → the global device-type list
includes hardware the installed runtime rejects. The launcher already selects
from the runtime's own supportedDeviceTypes; a hand-rolled simctl create
is what trips this.
serve-sim exited rc=… → read the printed log path. Usual causes: npx
could not reach the public registry (proxy), or the udid was shut down
externally. Fix and restart; do not loop more than twice.
Panel says the server stopped responding while the process is alive →
first confirm the URL is exactly the loopback one the launcher printed (never
substitute a hostname). Requires a dashboard whose CSP admits loopback
connect-src, since the panel's liveness probe is a no-cors fetch.
Boundaries
View-only. The user watches; whether taps forward at all depends on what
serve-sim's page itself offers. Never promise tap-through.
Do not edit the user's .xcodeproj, schemes, or build settings to force a
preview to work.
One mirror per simulator; multiple simulators mean multiple start calls.
Third-party dependency: serve-sim is fetched at runtime from public npm and
is not vendored.
