# CLAUDE.md - Developer Guide

This file provides guidance to Claude Code and developers working with this repository.

## Project Overview

iOS Simulator Skill is a production-ready Agent Skill providing 21 scripts for iOS app building, testing, and automation. It wraps Apple's `xcrun simctl` and Facebook's `idb` tools with semantic interfaces designed for AI agents and developers.

**Key Statistics:**
- 27 production scripts (~9,000 lines)
- 5 script categories (Build, Navigation, Testing, Permissions, Lifecycle)
- 7 shared utility modules (~2,400 lines)
- 100% token-optimized default output
- 88 unit tests across pipeline / sessions / token-budget / diff (run `pytest tests/`)

## Project Structure

```
ios-simulator-skill/            # Repository root
├── ios-simulator-skill/        # Distributable package
│   ├── .claude-plugin/
│   │   └── plugin.json        # Plugin manifest
│   └── skills/
│       └── ios-simulator-skill/
│           ├── SKILL.md       # Entry point (table of contents)
│           └── scripts/       # 27 production scripts
│               ├── build_and_test.py
│               ├── xcode/     # Xcode integration module
│               ├── log_monitor.py
│               ├── hang_watcher.py    # HangBuster session recorder + legacy stream
│               ├── screen_mapper.py
│               ├── navigator.py
│               ├── gesture.py
│               ├── keyboard.py
│               ├── app_launcher.py
│               ├── accessibility_audit.py
│               ├── visual_diff.py
│               ├── test_recorder.py
│               ├── app_state_capture.py
│               ├── clipboard.py
│               ├── status_bar.py
│               ├── push_notification.py
│               ├── privacy_manager.py
│               ├── simctl_boot.py
│               ├── simctl_shutdown.py
│               ├── simctl_create.py
│               ├── simctl_delete.py
│               ├── simctl_erase.py
│               ├── sim_health_check.sh
│               └── common/    # Shared utilities
│                   ├── hang_pipeline.py   # HangBuster filter pipeline (pure fns)
│                   └── hang_sessions.py   # HangBuster session storage
├── .github/workflows/
├── pyproject.toml
└── README.md
```

## Architecture Patterns

### Pattern 1: Class-Based Script Design

All scripts use class-based architecture for testability:

```python
class DeviceManager:
    def __init__(self, udid: str | None = None):
        self.udid = udid

    def execute(self, **kwargs) -> tuple[bool, str]:
        # Return (success, message) tuple
        pass

def main():
    parser = argparse.ArgumentParser()
    manager = DeviceManager(args.udid)
    success, message = manager.execute()
    print(message)
    sys.exit(0 if success else 1)
```

### Pattern 2: Auto-UDID Detection

All scripts support optional `--udid` with auto-detection:

```python
try:
    udid = resolve_device_identifier(args.udid)  # May be None
except RuntimeError as e:
    print(f"Error: {e}", file=sys.stderr)
    sys.exit(1)
```

### Pattern 3: Output Formatting

Consistent format across all scripts:

```
# Default (3-5 lines)
Device booted: iPhone 16 Pro (ABC123) [2.1s]

# --verbose (50+ lines)
Device booted successfully.
Device UDID: ABC123DEF456...
Boot time: 2.1 seconds

# --json (20-30 lines)
{"action": "boot", "udid": "ABC123", "success": true}
```

### Pattern 4: Batch Operations

Most scripts support batch operations:

```bash
python scripts/simctl_boot.py --all
python scripts/simctl_boot.py --type iPhone
```

## Script Categories

### Build & Development (2)
- **build_and_test.py**: Build with progressive disclosure
- **log_monitor.py**: Real-time log monitoring

### Navigation & Interaction (5)
- **screen_mapper.py**: Analyze screen
- **navigator.py**: Semantic element finding
- **gesture.py**: Touch simulation
- **keyboard.py**: Text input and keys
- **app_launcher.py**: App lifecycle

### Testing & Analysis (6)
- **accessibility_audit.py**: WCAG compliance
- **visual_diff.py**: Screenshot comparison
- **test_recorder.py**: Test documentation
- **app_state_capture.py**: Debugging snapshots
- **sim_health_check.sh**: Environment verification
- **hang_watcher.py** (HangBuster): session-scoped hang recorder with progressive disclosure (`--start`/`--stop`/`--get-details`/`--diff`); legacy `--watch`/`--since` paths preserved

### Advanced Testing & Permissions (4)
- **clipboard.py**: Clipboard management
- **status_bar.py**: Status bar control
- **push_notification.py**: Push notifications
- **privacy_manager.py**: Permission management

### Device Lifecycle Management (5)
- **simctl_boot.py**: Boot device
- **simctl_shutdown.py**: Shutdown device
- **simctl_create.py**: Create device
- **simctl_delete.py**: Delete device
- **simctl_erase.py**: Reset device

## Shared Utilities

### device_utils.py (~450 lines)
- `resolve_device_identifier()`: UDID/name/booted resolution
- `list_simulators()`: List with state filtering
- `_extract_device_type()`: Parse device type from name

### screenshot_utils.py (~346 lines)
- `capture_screenshot()`: File or inline mode
- `generate_screenshot_name()`: Semantic naming
- `resize_screenshot()`: Token optimization

### cache_utils.py (~258 lines)
- `ProgressiveCache`: Large output caching with TTL

### hang_pipeline.py (~630 lines)
Pure-function HangBuster filter pipeline (parse → normalise → threshold → bucket → cluster → aggregate → rank → format). Reusable but scoped — promote to a generic `log_filters.py` only when a second consumer appears (AHA).

- `parse_log_line()`, `normalise_message()`, `bucket_severity()`, `compute_fingerprint()`
- `cluster_events()`, `rank_clusters()`, aggregators (bursts/quiet/process)
- `format_l0/l1/l2()`, `format_cluster_detail()`, `format_diff()`
- `estimate_tokens()` (char/4 heuristic), `compress_to_budget()`
- `diff_sessions()` with `fingerprint_version` guard
- Dataclasses: `NormalisedEvent`, `Cluster`, `SessionSummary`, `Severity` (StrEnum)

### hang_sessions.py (~355 lines)
- `SessionStore`: filesystem-backed session repository at `~/.ios-simulator-skill/sessions/<id>/{meta.json, events.jsonl, summary.json}`
- Session ID format: `hang-YYYYMMDD-HHmmss-<4hex>` (random suffix avoids same-second collisions)
- Atomic meta writes (`.tmp` + `replace`); worker writes its own pid (no pidfile race)
- TTL prune via `IOS_SIM_HANG_SESSION_TTL_HOURS` on every `--start`

## Quality Standards

1. Type hints (modern Python syntax)
2. Docstrings on all functions
3. Specific exception handling
4. --help support on all scripts
5. Black formatter compliance
6. Ruff linter (0 errors)
7. Never use shell=True

## Token Efficiency

96% reduction in typical output:

- Default: 3-5 lines (5-10 tokens)
- Verbose: 50+ lines (400+ tokens)
- JSON: 20-30 lines (20-30 tokens)

This keeps AI agent conversations focused and cost-effective.

## Contributing

New scripts should:
- Use class-based design for > 50 lines of logic
- Support --udid and auto-detection
- Support --json output
- Provide --help documentation
- Follow Black and Ruff standards
- Update SKILL.md table of contents
- Work with real simulators before submission

## Release Process

1. Update version in SKILL.md frontmatter, pyproject.toml
2. Verify CI passes (Black, Ruff)
3. Create GitHub release with vX.X.X tag
4. Attach zipped ios-simulator-skill/ directory

## Design Philosophy

**Semantic**: Find elements by meaning, not pixels.

**Progressive**: Minimal output by default, details on demand.

**Accessible**: Built on standard iOS accessibility APIs.

**Zero-Config**: Works immediately with no setup.

**Structured**: JSON and formatted text, not raw logs.

**Reusable**: Common patterns across all scripts.

This design works for both developers and AI agents.