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ios-simulator-skill — Claude Code skill: build and test iOS apps

Thirty Python scripts to build, test, and control iOS apps in Simulator. Navigate by accessibility labels instead of screenshots, manage logs, simulate GPS and appearance—all via structured data instead of pixel analysis.

Install into Claude Code · Skills CLI (Vercel) All methods and platforms ↓
npx skills add conorluddy/ios-simulator-skill --skill ios-simulator-skill -a claude-code
Open on GitHub

What ios-simulator-skill does

This skill bundles 30 ready-made scripts for Xcode and iOS Simulator. Instead of parsing screenshots (token-heavy), it reads the accessibility tree—element types, labels, and tap targets as structured data. Finding elements by label or type is faster and more reliable than image search.

Scripts cover building projects, running tests, and streaming logs; navigating UI via semantic search, taps, text input, swipes, and scrolling; configuring the simulator with dark mode, font size, GPS, language, and region. Each script supports --json for machine-readable output and --help for full details.

Requires macOS, Xcode, Python 3.12+, and idb. Scripts live in scripts/ next to SKILL.md; run them by absolute path from your project root so relative Xcode project paths resolve correctly.

What it helps with

  • Build an Xcode project, run unit tests, and parse build errors
  • Launch an app on Simulator and tap buttons by their accessibility label
  • Enter text into fields, swipe or scroll, check toggle state
  • Take a screenshot, compare two screenshots, audit accessibility
  • Stream logs, diagnose hangs or crashes, switch to dark mode or change language

Example prompts for the agent

  • Build this project in Simulator and run unit tests
  • Launch the app on Simulator, find the Login button and tap it
  • On the current screen, find a text field and enter [email protected]

How to install ios-simulator-skill

1Skills CLI (Vercel)

npx skills add conorluddy/ios-simulator-skill --skill ios-simulator-skill -a claude-code

2Manually: put the files in place

~/.claude/skills/ios-simulator-skill/SKILL.md

Copy the whole skill folder; for one project use .claude/skills/ios-simulator-skill/

Step by step, with commands for each platform: How to install skills in Claude Code: five ways

Questions about ios-simulator-skill

How do I install ios-simulator-skill in Claude Code?

Run npx skills add conorluddy/ios-simulator-skill --skill ios-simulator-skill -a claude-code. The skill will be available at ~/.claude/skills/ios-simulator-skill/SKILL.md.

What does ios-simulator-skill do?

It provides 30 scripts for building iOS apps, running tests, navigating UI by element label or type, taking and comparing screenshots, streaming logs, and configuring Simulator (GPS, locale, appearance, accessibility).

What are the system requirements?

macOS, Xcode, Python 3.12 or later, and idb. This skill runs on Mac only.

Source text

SKILL.md · MIT
---
name: ios-simulator-skill
version: 1.7.0
description: Build, test, and drive iOS apps in the Simulator with 30 token-efficient scripts. Use when asked to build or test an Xcode project, launch an app on a simulator, tap/type/swipe through its UI by accessibility label, take screenshots or visual diffs, audit accessibility, read logs or diagnose hangs, or manage simulators (boot, erase, permissions, location, push, appearance). macOS only; needs Xcode, Python 3.12+ and idb.
---

# iOS Simulator Skill

Build, test, and automate iOS applications using accessibility-driven navigation and structured data instead of pixel coordinates.

## Quick Start

```bash
# 1. Check environment
bash scripts/sim_health_check.sh

# 2. Launch app
python3 scripts/app_launcher.py --launch com.example.app

# 3. Map screen to see elements
python3 scripts/screen_mapper.py

# 4. Tap button
python3 scripts/navigator.py --find-text "Login" --tap

# 5. Enter text
python3 scripts/navigator.py --find-type TextField --enter-text "[email protected]"
```

**Paths:** `scripts/` is relative to the directory containing this SKILL.md, not the user's project.
Examples write `scripts/...` for brevity; run them by absolute path from the user's project
(e.g. `python3 <skill-dir>/scripts/navigator.py ...`) so relative Xcode project paths still resolve.

All scripts support `--help` for detailed options; most support `--json` for machine-readable output.

## Navigation Strategy

**Always prefer the accessibility tree over screenshots for navigation.** The accessibility tree gives you element types, labels, frames, and tap targets — structured data that's cheaper and more reliable than image analysis.

Use this priority:
1. `screen_mapper.py` → structured element list (5-7 lines, ~10 tokens)
2. `navigator.py --find-text/--find-type/--find-id` → semantic interaction
3. Screenshots → only for visual verification, bug reports, or visual diff

Screenshots cost 1,600–6,300 tokens depending on size. The accessibility tree costs 10–50 tokens in default mode.

## 30 Production Scripts

### Build & Development (2 scripts)

1. **build_and_test.py** - Build Xcode projects, run tests, parse results with progressive disclosure
   - Build with live result streaming
   - Parse errors and warnings from xcresult bundles
   - Retrieve detailed build logs on demand
   - Options: `--project`, `--scheme`, `--clean`, `--test`, `--verbose`, `--json`

2. **log_monitor.py** - Real-time log monitoring with intelligent filtering
   - Stream logs or capture by duration
   - Filter by severity (error/warning/info/debug)
   - Deduplicate repeated messages
   - Options: `--app`, `--severity`, `--follow`, `--duration`, `--output`, `--json`

### Device State (3 scripts)

3. **appearance.py** - Control simulator appearance: dark mode, Dynamic Type size, contrast, and locale/region
   - Toggle light/dark theme via `xcrun simctl ui`
   - Set Dynamic Type size with friendly aliases (XS through AX5)
   - `--contrast high|normal` toggles Increase Contrast and reads it back to confirm; `--reset` also restores normal contrast
   - Write locale and region defaults; optional app restart via `--bundle-id`
   - RTL flagged automatically for ar/he/fa/ur/yi locales
   - Options: `--theme`, `--text-size`, `--contrast`, `--locale`, `--region`, `--reset`, `--bundle-id`, `--udid`, `--json`, `--verbose`

4. **location.py** - Simulate GPS coordinates, named city presets, and GPX scenario playback
   - Fix a coordinate with `--lat`/`--lng` or pick a city with `--city`
   - Play a built-in scenario (City Run, Freeway Drive, etc.) via `--gpx <scenario>`
   - Animate multi-waypoint paths with configurable speed via `--waypoints` and `--speed`
   - Clear simulated location with `--clear`; list available scenarios with `--list-scenarios`
   - Options: `--lat`, `--lng`, `--city`, `--gpx`, `--waypoints`, `--speed`, `--clear`, `--list-scenarios`, `--udid`, `--json`, `--verbose`

5. **media.py** - Seed or empty the photo library for photo-picker tests
   - `--add a.jpg b.png` via `xcrun simctl addmedia`
   - `--clear --yes` empties the library via `idb photos clear` (idb 1.7+); `--clear --yes --add` leaves exactly the added files
   - Without `--yes`, `--clear` refuses if the library has photos (they can't be recovered): ask the user first
   - Fails fast on a missing file
   - Options: `--add`, `--clear`, `--yes`, `--udid`, `--json`

### Navigation & Interaction (5 scripts)

6. **screen_mapper.py** - Analyze current screen and list interactive elements
   - Element type breakdown
   - Interactive button list
   - Text field status
   - If labelled elements cover under 10% of the screen, adds a `Coverage:` line suggesting `--deep`
   - `--deep` reads through idb's axbridge backend (idb 1.7+): also sees Safari/WKWebView content
     and in-app alerts the default read misses, plus many unlabelled container views. It turns on
     the device's accessibility automation mode (not restored afterwards). Web-content frames are
     relative to the web view, so use `--deep` to find elements, not to take tap coordinates
   - Options: `--verbose`, `--hints`, `--deep`, `--json`

7. **navigator.py** - Find and interact with elements semantically
   - Find by text (fuzzy, or exact with `--find-exact`); interactive leaf elements rank above containers sharing the label
   - Find by element type
   - Find by accessibility ID
   - Enter text or tap elements
   - `--tap` on a Button/Link/Switch/CheckBox/Tab with a unique accessibility ID or label uses an accessibility press
     (idb 1.7+), so overlays like a floating search bar can't intercept it; output says
     `(accessibility press)`. Otherwise it taps the frame center
   - `--set-value TEXT` replaces a field's value without the keyboard (any characters, idb 1.7+).
     Focus doesn't move, so use `--enter-text` when a Return key must submit afterwards
     The value is read back before success is claimed (not for secure fields); a mismatch exits 1
   - `--tap --expect VALUE` taps only if the element's value is VALUE (toggles: `1` on, `0` off) and
     exits 1 without tapping otherwise, so "turn X off" is safe to repeat
   - iOS 27 reports toggles as `CheckBox`. Only a press flips them (no HID touch does, even on the
     switch itself); if neither ID nor label is unique, the output warns to check the value
   - A frozen app stalls every read and tap until its main thread responds
   - Failures include idb's stderr (e.g. a dead companion)
   - Options: `--find-text`, `--find-exact`, `--find-type`, `--find-id`, `--index`, `--tap`, `--expect`, `--tap-at`, `--enter-text`, `--set-value`, `--list`

8. **gesture.py** - Perform swipes, scrolls, pinches, and complex gestures
   - Directional swipes (up/down/left/right) - `--swipe` is the direction the finger moves
   - Multi-swipe scrolling - `--scroll` is the direction the content moves (`down` reveals content below)
   - Pinch zoom via `idb ui pinch` (`--pinch out` zooms in; `--scale` sets an explicit factor)
   - Long press via `idb ui tap --duration`
   - Pull to refresh
   - `--double-tap X,Y [--tap-count N]` - multi-tap at a point (idb 1.7+)
   - `--drag SOURCE DEST` - press-hold, drag, release; each end is `x,y` or an accessibility label,
     e.g. `--drag "Row 1" "Row 4"` (idb 1.7+)
   - `--rotate portrait|portrait-upside-down|landscape-left|landscape-right` - physical device rotation (idb 1.7+)
   - `--shake` - shake the device, for debug menus and undo (idb 1.7+)
   - Options: `--swipe`, `--swipe-from/--swipe-to`, `--scroll`, `--scroll-amount`, `--pinch`, `--scale`, `--long-press`, `--duration`, `--refresh`, `--double-tap`, `--tap-count`, `--drag`, `--rotate`, `--shake`

9. **keyboard.py** - Text input and hardware button control
   - Type text (fast or slow; ASCII only)
   - Special keys (return, delete, tab, space, escape, arrows), single letters, or raw HID codes
   - Key sequences (`--key-sequence h,i,return`)
   - Key chords: `--key z --command --shift` (redo); `--shift/--control/--option` need idb 1.7+
   - Clear the focused field (Cmd+A, delete)
   - Hardware buttons: home, lock/power, side, siri, apple-pay, volume-up/down (volume needs idb 1.6.3+)
   - Options: `--type`, `--slow`, `--key`, `--shift`, `--control`, `--option`, `--command`, `--count`, `--key-sequence`, `--button`, `--clear`, `--dismiss`

10. **app_launcher.py** - App lifecycle management
   - Launch apps by bundle ID
   - Terminate apps
   - Install/uninstall from .app bundles (`--uninstall` needs `--yes`: the app's data is deleted)
   - Deep link navigation
   - List installed apps
   - Check app state
   - Pass launch arguments (`--args`) and environment variables (`--env KEY=VALUE`, injected as `SIMCTL_CHILD_*`) to the app on launch/restart
   - Options: `--launch`, `--terminate`, `--restart`, `--install`, `--uninstall`, `--yes`, `--open-url`, `--list`, `--state`, `--args`, `--env`, `--wait-for-debugger`

### Testing & Analysis (9 scripts)

11. **accessibility_audit.py** - Check WCAG compliance on current screen
    - Critical issues (missing labels, empty buttons, no alt text)
    - Warnings (missing hints, small touch targets)
    - Info (missing IDs, deep nesting)
    - Options: `--verbose`, `--output`, `--json`

12. **visual_diff.py** - Compare two screenshots for visual changes
    - Pixel-by-pixel comparison
    - Threshold-based pass/fail
    - Generate diff images
    - Options: `--threshold`, `--output`, `--details`, `--json`

13. **test_recorder.py** - Automatically document test execution
    - Capture screenshots and accessibility trees per step
    - Generate markdown reports with timing data
    - Options: `--test-name`, `--output`, `--verbose`, `--json`

14. **app_state_capture.py** - Create comprehensive debugging snapshots
    - Screenshot, UI hierarchy, app logs, device info
    - Markdown summary for bug reports
    - Options: `--app-bundle-id`, `--output`, `--log-lines`, `--json`

15. **sim_health_check.sh** - Verify environment is properly configured
    - Check macOS, Xcode, simctl, IDB, Python
    - List available and booted simulators
    - Verify Python packages (Pillow)

16. **model_inspector.py** - Inspect Core Data and SwiftData models from project files
    - Parse .xcdatamodeld packages (entities, attributes, relationships)
    - Detect model versions and current active version
    - Best-effort SwiftData @Model class extraction
    - Raw source dump for any model on demand (`--raw ModelName`)
    - Options: `--project-path`, `--core-data-only`, `--swiftdata-only`, `--show-versions`, `--raw`, `--verbose`, `--json`

17. **container.py** - Inspect app sandbox: files, UserDefaults, and Core Data store paths
    - List data container files at configurable depth via `--ls`
    - Read files with auto-detected plist decoding via `--cat` (large files cached)
    - Dump UserDefaults as key=value or JSON via `--userdefaults`
    - Locate `.sqlite` / `.sqlite-wal` / `.sqlite-shm` stores via `--core-data-path`
    - Export full container snapshot via `--export`
    - Options: `--ls`, `--cat`, `--userdefaults`, `--core-data-path`, `--export`, `--udid`, `--json`, `--verbose`

18. **hang_watcher.py** (HangBuster) - Record + summarise os_log hang events with progressive disclosure
    - **Session mode (HangBuster, agent-native):** start a detached recorder, interact with the simulator, stop for a token-tight summary
      - `--start` → returns a session ID; detached worker normalises + thresholds events on the fly
      - `--stop SESSION_ID` → emits ~80–120 token L1 summary (header + top-N clusters + drill hint)
      - `--get-details SESSION_ID [--cluster N | --raw]` → L2 full clusters or L3 per-event detail
      - `--list-sessions` / `--clear-sessions [--older-than 24h]` / `--diff A B` (cross-session regression report)
      - Filter pipeline: parse → normalise → threshold → bucket → cluster → aggregate → rank → format (in `common/hang_pipeline.py`)
      - `--budget-tokens N` picks the densest level (L0/L1/L2) that fits; `--terse` forces L0
      - `--auto-sample` captures a main-thread stack on first event per cluster (soft dependency: `main_thread_sampler.py` #62; graceful no-op if absent)
    - **Raw capture mode (full fidelity for `jq` exploration):** skip the clustering pipeline, dump every matching log line verbatim to `raw.ndjson`
      - `--start --raw-capture [--max-size-mb 10] [--no-gzip]` — spawns `log stream --style ndjson`
      - Per-session size cap (`--max-size-mb`, default 10) — worker stops cleanly on cap; `extras.truncated=true`
      - `--stop` gzips `raw.ndjson` → `raw.ndjson.gz` (~15–19× compression; `--no-gzip` opts out)
      - `--get-details SESSION_ID` on a raw session prints the path with a `zcat | jq ...` hint
    - **Resilience (auto-restart on stream death):** EOF or subprocess death triggers a `stream_died` event then a bounded restart with 2s backoff. After `IOS_SIM_HANG_MAX_RESTARTS` (default 3) the session is marked `crashed`, never left in stale `running` state. `--list-sessions` shows `capture=Xs` and `restarts=N`.
    - **Cleanup is automatic:** TTL prune (`IOS_SIM_HANG_SESSION_TTL_HOURS`, default 24h) + aggregate cap (`IOS_SIM_HANG_TOTAL_CAP_MB`, default 100 MB, oldest-first eviction) both run on every `--start`.
    - **Legacy modes (unchanged for backward compat):** `--watch [--duration N]` (live stream) and `--since 5m` (historical)
    - Filters: `--bundle-id` (post-parse — hang capture stays simulator-global so RunningBoard/SpringBoard events are kept), `--predicate` (also via `IOS_SIM_HANG_PREDICATE`)
    - All output supports `--json`; session storage at `~/.ios-simulator-skill/sessions/<id>/{meta.json,events.jsonl,summary.json,raw.ndjson.gz}`

    **Quick start (summarised mode):**
    ```bash
    SID=$(python3 scripts/hang_watcher.py --start --min-hang-ms 200)
    # ... interact with the simulator (open sheets, scroll, navigate) ...
    python3 scripts/hang_watcher.py --stop $SID                  # token-tight L1 summary
    python3 scripts/hang_watcher.py --get-details $SID --cluster 1  # drill into cluster 1
    python3 scripts/hang_watcher.py --diff $SID_BASELINE $SID    # cross-session regression
    ```

    **Quick start (raw capture + `jq` exploration):**
    ```bash
    SID=$(python3 scripts/hang_watcher.py --start --raw-capture --max-size-mb 5)
    # ... interact with the simulator ...
    python3 scripts/hang_watcher.py --stop $SID
    # → "Session ...: raw mode, 737 lines, 0.96 MB → 0.05 MB gzipped"

    # Top processes by event count:
    zcat ~/.ios-simulator-skill/sessions/$SID/raw.ndjson.gz \
      | jq -s 'group_by(.processImagePath) | map({proc: (.[0].processImagePath | split("/") | last), n: length}) | sort_by(-.n) | .[:5]'

    # All RunningBoard assertion invalidations:
    zcat .../raw.ndjson.gz | jq -c 'select(.subsystem == "com.apple.runningboard" and (.eventMessage | startswith("Invalidating")))'

    # Hangs per minute:
    zcat .../raw.ndjson.gz | jq -r '.timestamp[:16]' | sort | uniq -c
    ```

19. **localization_audit.py** - Detect string catalog gaps, missing keys, and placeholder mismatches
    - Report missing and `needs_review`/`new` keys per locale in `.xcstrings` catalogs
    - Cross-reference catalog keys against Swift source (`String(localized:)` / `NSLocalizedString`) via `--source`
    - Flag placeholder count mismatches (`%d`, `%@`, `%s`, `%lld`) across locales
    - Legacy `.strings` and `.stringsdict` support via `plistlib`
    - CI-friendly `--strict` exits 2 on any finding
    - Options: `--catalog`, `--source`, `--locale`, `--strict`, `--json`, `--verbose`

### Advanced Testing & Permissions (4 scripts)

20. **clipboard.py** - Manage simulator clipboard for paste testing
    - Copy text to clipboard
    - Test paste flows without manual entry
    - Options: `--copy`, `--test-name`, `--expected`, `--json`

21. **status_bar.py** - Override simulator status bar appearance
    - Presets: clean (9:41, 100% battery), testing (11:11, 50%), low-battery (20%), airplane (offline)
    - Custom time, network, battery, WiFi settings
    - Options: `--preset`, `--time`, `--data-network`, `--battery-level`, `--clear`, `--json`

22. **push_notification.py** - Send simulated push notifications
    - Simple mode (title + body + badge)
    - Custom JSON payloads
    - Test notification handling and deep links
    - `--list` shows delivered notifications; `--clear` withdraws them all (both idb 1.7+; sending stays on simctl)
    - A push sent while its app is in the foreground isn't delivered to Notification Center, so `--list` won't show it
    - Options: `--bundle-id`, `--title`, `--body`, `--badge`, `--payload`, `--list`, `--clear`, `--json`

23. **privacy_manager.py** - Grant, revoke, and reset app permissions
    - 13 supported services (camera, microphone, location, contacts, photos, calendar, health, etc.)
    - Batch operations (comma-separated services)
    - Audit trail with test scenario tracking
    - Options: `--bundle-id`, `--grant`, `--revoke`, `--reset`, `--list`, `--json`

### Simulator Discovery (2 scripts)

24. **sim_list.py** - List simulators with progressive disclosure
    - Concise summary by default (total / available / booted)
    - Full details on demand via cache IDs
    - Filter by device type
    - Suggest recommended simulators with `--suggest`
    - 96% token reduction vs raw `simctl list` (57k → 2k tokens)
    - Options: `--get-details`, `--suggest`, `--device-type`, `--json`

25. **simulator_selector.py** - Suggest the best simulator for the job
    - Ranks candidates by recent use (from `config.json`), latest iOS, common test models, and boot status
    - List all available simulators with `--list`
    - Boot a selected simulator directly with `--boot`
    - JSON output for programmatic use
    - Options: `--suggest`, `--list`, `--boot`, `--json`

### Device Lifecycle Management (5 scripts)

26. **simctl_boot.py** - Boot simulators with optional readiness verification
    - Boot by UDID or device name
    - Wait for device ready with timeout
    - Batch boot operations (--all, --type)
    - Performance timing
    - Options: `--udid`, `--name`, `--wait-ready`, `--timeout`, `--all`, `--type`, `--json`

27. **simctl_shutdown.py** - Gracefully shutdown simulators
    - Shutdown by UDID or device name
    - Optional verification of shutdown completion
    - Batch shutdown operations
    - Options: `--udid`, `--name`, `--verify`, `--timeout`, `--all`, `--type`, `--json`

28. **simctl_create.py** - Create simulators dynamically
    - Create by device type and iOS version
    - List available device types and runtimes
    - Custom device naming
    - Returns UDID for CI/CD integration
    - Options: `--device`, `--runtime`, `--name`, `--list-devices`, `--list-runtimes`, `--json`

29. **simctl_delete.py** - Permanently delete simulators
    - Delete by UDID or device name
    - Refuses without `--yes` (no prompt; the simulator and its data can't be recovered): ask the user first
    - Batch delete operations
    - Smart deletion (--old N to keep N per device type)
    - Options: `--udid`, `--name`, `--yes`, `--all`, `--type`, `--old`, `--json`

30. **simctl_erase.py** - Factory reset simulators without deletion
    - Preserve device UUID (faster than delete+create)
    - Erase all, by type, or booted simulators
    - Optional verification
    - Refuses without `--yes` (apps, data and settings can't be recovered): ask the user first
    - Options: `--udid`, `--name`, `--yes`, `--verify`, `--timeout`, `--all`, `--type`, `--booted`, `--json`

## Common Patterns

**Auto-UDID Detection**: Most scripts auto-detect the booted simulator if --udid is not provided.

**Device Name Resolution**: Use device names (e.g., "iPhone 16 Pro") instead of UDIDs - scripts resolve automatically.

**Batch Operations**: Many scripts support `--all` for all simulators or `--type iPhone` for device type filtering.

**Output Formats**: Default is concise human-readable output. Use `--json` for machine-readable output in CI/CD.

**Help**: All scripts support `--help` for detailed options and examples.

**Screenshot Sizing**: Screenshots are resized to save tokens. Presets: `full` (3-4 tiles, ~5K tokens), `half` (1 tile, ~1.6K tokens, default), `quarter` (1 tile, ~800 tokens, less detail). Use `quarter` for quick visual checks, `half` for readable UI, `full` only when pixel-level detail matters. Scripts that capture screenshots (`app_state_capture.py`, `test_recorder.py`) default to `half`.

## Typical Workflow

1. Verify environment: `bash scripts/sim_health_check.sh`
2. Launch app: `python3 scripts/app_launcher.py --launch com.example.app`
3. Analyze screen: `python3 scripts/screen_mapper.py`
4. Interact: `python3 scripts/navigator.py --find-text "Button" --tap`
5. Verify: `python3 scripts/accessibility_audit.py`
6. Debug if needed: `python3 scripts/app_state_capture.py --app-bundle-id com.example.app`

## Configuration

Most operational limits can be tuned via environment variables. Defaults work for typical local development; raise them for slow CI runners, large monorepo builds, or accessibility audits on complex screens.

| Variable | Default | Controls |
|---|---|---|
| `IOS_SIM_A11Y_LABEL_MAX` | `80` | Max chars of `AXLabel` retained in accessibility audit output |
| `IOS_SIM_A11Y_TOP_ISSUES` | `10` | Top accessibility issues surfaced per audit |
| `IOS_SIM_APPS_PREVIEW` | `30` | App entries listed by `app_launcher.py` before truncation |
| `IOS_SIM_BOOT_SUBPROCESS_TIMEOUT` | `60` | Timeout for the `simctl boot` subprocess itself (seconds) |
| `IOS_SIM_BOOT_TIMEOUT` | `300` | Wait-for-ready timeout after boot (seconds) |
| `IOS_SIM_BUILD_JSON_CAP` | `50` | Max build errors / failed tests in JSON output |
| `IOS_SIM_BUILD_LOG_PREVIEW` | `4000` | Chars of build log preview in default output |
| `IOS_SIM_BUILD_TIMEOUT` | `1800` | Max seconds for an `xcodebuild build` invocation before kill |
| `IOS_SIM_INTROSPECT_TIMEOUT` | `60` | Timeout for `xcodebuild -list` and `simctl list` lookups (seconds) |
| `IOS_SIM_TEST_TIMEOUT` | `2700` | Max seconds for an `xcodebuild test` invocation before kill |
| `IOS_SIM_BUILD_SUMMARY_CAP` | `15` | Errors/failures in default build summary |
| `IOS_SIM_BUILD_VERBOSE_CAP` | `100` | Errors/warnings in verbose build output |
| `IOS_SIM_CACHE_MAX_ENTRIES` | `500` | Max entries in progressive disclosure cache (LRU eviction) |
| `IOS_SIM_CACHE_TTL_HOURS` | `1` | Cache entry expiration |
| `IOS_SIM_ERASE_TIMEOUT` | `90` | Wait-for-erase timeout (seconds) |
| `IOS_SIM_HANG_PREDICATE` | _(default)_ | Override the `os_log` predicate used by `hang_watcher.py` (default catches RunningBoard kills + "Hang detected" + main-thread hangs). Hang events originate from system daemons (RunningBoard, SpringBoard) so the predicate stays simulator-global — `--bundle-id` is applied post-parse, not ANDed in. |
| `IOS_SIM_HANG_MIN_MS` | `250` | HangBuster threshold — events below this duration never reach disk (smaller = more sensitive, larger summaries) |
| `IOS_SIM_HANG_SESSION_TTL_HOURS` | `24` | HangBuster session prune age; pruning runs on every `--start` |
| `IOS_SIM_HANG_DEFAULT_TOP_N` | `3` | Default top-N clusters in `--stop` L1 output |
| `IOS_SIM_HANG_BUDGET_TOKENS` | _(unset)_ | Default token budget for `--stop` (picks L0/L1/L2 to fit) |
| `IOS_SIM_HANG_MAX_RESTARTS` | `3` | HangBuster worker: max `log stream` respawn attempts on EOF/subprocess death before the session is marked `crashed` |
| `IOS_SIM_HANG_TOTAL_CAP_MB` | `100` | HangBuster aggregate disk cap. When total session-state exceeds this on `--start`, oldest sessions are dropped first. Set to `0` to disable. |
| `IOS_SIM_LOG_JSON_CAP` | `100` | Max errors/warnings in `log_monitor.py` JSON output |
| `IOS_SIM_LOG_LINE_MAX` | `300` | Per-line truncation in log summaries |
| `IOS_SIM_LOG_TAIL` | `200` | Lines of log tail in verbose / sample output |
| `IOS_SIM_LOG_TEXT_SUMMARY` | `15` | Errors/warnings shown in text-mode log summary |
| `IOS_SIM_MAX_ELEMENTS` | `25` | Items listed by `navigator.py --list` and `push_notification.py --list` |
| `IOS_SIM_POLL_INTERVAL` | `0.5` | Boot/erase state polling interval (seconds) |
| `IOS_SIM_RELAUNCH_DELAY_MS` | `1000` | Delay between terminate and re-launch in `app_launcher.py` |
| `IOS_SIM_SCREEN_BUTTONS_PREVIEW` | `15` | Button names listed by `screen_mapper.py` |
| `IOS_SIM_SCREEN_SECTION_ITEMS` | `10` | Items per section shown by `screen_mapper.py` |
| `IOS_SIM_STATE_SUBPROCESS_TIMEOUT` | `15` | Subprocess timeout in `app_state_capture.py` (seconds) |
| `IOS_SIM_TAP_SETTLE_MS` | `500` | Post-tap settle delay in `navigator.py` |

Example:

```bash
# Slow GitHub Actions runner: give boot 10 minutes
IOS_SIM_BOOT_TIMEOUT=600 python3 scripts/simctl_boot.py --wait-ready
```

## Requirements

- macOS 15 (Sequoia)+
- Xcode 26+ (the full app; Command Line Tools alone are not enough for idb)
- Apple silicon Mac (the Homebrew idb build is arm64-only)
- Python 3.12+
- `idb` **1.5.1+** (1.6.3+ recommended) - required for every interactive script (tap, swipe, type):
  `brew install facebook/fb/idb` (installs both idb-cli and idb-companion)
- Pillow, for visual diffs only: `pip3 install pillow`

Verify with `bash scripts/sim_health_check.sh` (add `--json` for structured output).

## Troubleshooting

**Taps, swipes and typing do nothing, but reads work.** `idb` reports success and the screen
never changes. On Xcode 27 this means `idb-companion` is older than 1.5.1: it looks for
`SimulatorKit.framework` at the path Xcode 26 used. Upgrade both together, then restart running
companions: `brew upgrade facebook/fb/idb-cli facebook/fb/idb-companion && idb kill`.

**`SimulatorKit is required for HID interactions`.** Same cause, same fix.

**Health check warns "idb companions started before idb-companion was last installed".** Those
companions still run the pre-upgrade binary. Run `idb kill`; the next idb call starts a fresh one.

**`Connection refused` or `No such file` from every idb call.** A dead companion is still in
idb's registry at `/tmp/idb/state`, so idb dials a socket nobody is listening on instead of
starting a fresh companion. Fix: `idb disconnect <udid>`.

**`open -a Simulator` fails.** Xcode 27 has no `Simulator.app`; it was replaced by
`DeviceHub.app` in `Xcode.app/Contents/Applications/`. Boot headlessly instead:
`xcrun simctl boot <udid>`. Note that quitting DeviceHub shuts down the simulator it hosts.

**`idb: command not found`.** The companion and the CLI are separate packages;
`brew install facebook/fb/idb` installs both. If `which -a idb` shows more than one, the first on
`PATH` wins. An old pip `fb-idb` there needs `pip uninstall fb-idb`.

**Known upstream idb issues** (open as of idb 1.7.6):
- [facebook/idb#964](https://github.com/facebook/idb/issues/964): on some iOS 26+ screens
  `describe-all` returns only the application node, and SpringBoard alerts can't be tapped. The
  default `ax` backend can't see across process boundaries; try
  `idb ui describe-all --json --api axbridge`. Tap coordinates are points, not screenshot pixels.
  After an app relaunch the default read can also stay stuck on a single zero-size Application
  node; one `screen_mapper.py --deep` read (which may itself time out once) brings it back.
- [facebook/idb#978](https://github.com/facebook/idb/issues/978): accessibility custom actions
  are listed by `describe-all` but can't be performed.
- [facebook/idb#954](https://github.com/facebook/idb/issues/954): the Homebrew build is
  arm64-only, so Intel Macs are unsupported.

## Documentation

- **SKILL.md** (this file) - Script reference, requirements, troubleshooting
- **[README.md](https://github.com/conorluddy/ios-simulator-skill/blob/main/README.md)** - Installation, updating idb, Xcode 27 notes
- **[AGENTS.md](https://github.com/conorluddy/ios-simulator-skill/blob/main/AGENTS.md)** - Architecture and implementation details

## Key Design Principles

**Semantic Navigation**: Find elements by meaning (text, type, ID) not pixel coordinates. Survives UI changes.

**Token Efficiency**: Concise default output (3-5 lines) with optional verbose and JSON modes for detailed results.

**Accessibility-First**: Built on standard accessibility APIs for reliability and compatibility.

**Zero Configuration**: Works immediately on any macOS with Xcode. No setup required.

**Structured Data**: Scripts output JSON or formatted text, not raw logs. Easy to parse and integrate.

**Auto-Learning**: Build system remembers your device preference. Configuration stored per-project.

---

Use these scripts directly or let Claude Code invoke them automatically when your request matches the skill description.

© conorluddy · MIT · conorluddy/ios-simulator-skill

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