tolaria/docs/IPAD-PROTOTYPE.md

# iPad Prototype — Tauri v2 iOS Feasibility Report

**Date:** 2026-03-27
**Status:** VERIFIED — App builds, installs, and renders React UI on iPad Pro 13" simulator (iOS 18.3.1)

## Summary

Laputa can be ported to iPad using Tauri v2 iOS (beta) with **minimal code changes**. The React frontend stays identical. The Rust backend compiles for iOS with conditional compilation to gate desktop-only features (git CLI, menu bar, MCP, Claude CLI). Vault read/write operations work without changes.

**Key result:** `tauri ios build --target aarch64-sim` succeeds. The app launches on iPad simulator and the React UI renders correctly (telemetry consent dialog, welcome screen, all styled correctly).

## What Works

| Feature | Status | Notes |
|---------|--------|-------|
| Rust backend cross-compilation | VERIFIED | Zero errors, zero warnings for `aarch64-apple-ios-sim` |
| Desktop build (no regressions) | VERIFIED | 581 Rust tests pass, 2201 frontend tests pass, CodeScene gates pass |
| Tauri iOS project generation | VERIFIED | `tauri ios init` generates Xcode project successfully |
| Xcode build for simulator | VERIFIED | `tauri ios build --target aarch64-sim` — **BUILD SUCCEEDED** |
| App launch on iPad simulator | VERIFIED | Installs and launches on iPad Pro 13" (M4), PID assigned |
| React UI in WebView | VERIFIED | Telemetry consent dialog renders with correct styling, fonts, buttons |
| Vault file read/write | Expected to work | Pure filesystem operations, no process spawning |
| AI chat (Anthropic API) | Expected to work | Uses `reqwest` HTTP, no CLI dependency |
| Search | Expected to work | Pure Rust in-memory search |
| Settings persistence | Expected to work | JSON file read/write |

## What Doesn't Work (Yet)

| Feature | Blocker | Recommended Solution |
|---------|---------|---------------------|
| Git operations | No `git` binary on iOS | **Option B (Working Copy)** for prototype; **Option A (isomorphic-git)** for production |
| GitHub clone/push/pull | Depends on git CLI | Same as above |
| Claude CLI streaming | No `claude` binary on iOS | Use Anthropic API directly (requires new implementation) |
| MCP server / WS bridge | Spawns Node.js child process | Skip for mobile; explore in-process MCP later |
| macOS menu bar | Desktop-only API | Touch-native navigation (already handled by React) |
| Updater plugin | Desktop-only | Use TestFlight for updates |
| File open dialog | Different on iOS | `tauri-plugin-dialog` supports iOS — needs testing |

## Changes Made

### `src-tauri/src/lib.rs`
- Gated `WsBridgeChild`, `run_startup_tasks`, `spawn_ws_bridge`, `log_startup_result` behind `#[cfg(desktop)]`
- Mobile build skips MCP registration, WS bridge, and vault migrations at startup
- Run event handler gated for desktop (child process cleanup)

### `src-tauri/src/commands.rs`
- Git commands: desktop implementations remain unchanged; mobile stubs return graceful errors or empty results
- GitHub commands: desktop-only; mobile stubs return errors
- Claude CLI commands: desktop-only; mobile stubs return `installed: false`
- MCP commands: desktop-only; mobile stubs return `NotInstalled`
- Menu commands: desktop-only; mobile stub is a no-op
- Vault, frontmatter, search, AI chat, settings: **unchanged** (work on both platforms)

### `src-tauri/src/lib.rs`
- `pub mod menu` gated behind `#[cfg(desktop)]`

### `src-tauri/capabilities/`
- `default.json`: scoped to desktop platforms (`linux`, `macOS`, `windows`)
- `mobile.json`: new file with iOS/Android permissions (core, dialog)

### `src-tauri/gen/apple/`
- Full Xcode project generated by `tauri ios init`
- iPad support: all orientations enabled, arm64 architecture

## Architecture: How Mobile Stubs Work

```
Frontend (React) ──invoke──> Tauri Commands ──> Rust Backend
                                 │
                      ┌──────────┴──────────┐
                  #[cfg(desktop)]       #[cfg(mobile)]
                      │                     │
                  Real impl            Stub (error/empty)
                  (git CLI,            (graceful degradation)
                   menu, MCP)
```

The frontend code doesn't change at all. Commands that aren't available on mobile return errors that the UI can handle gracefully (e.g., hiding the git sync panel, disabling commit buttons).

## Git Strategy for iPad

### Phase 1: Working Copy (Recommended for prototype)
- User manages vault with [Working Copy](https://workingcopy.app/) (git client for iPad)
- Laputa opens the vault via iOS Files API / FileProvider
- Zero git code needed in Laputa — Working Copy handles sync
- **Pro:** Works immediately, robust git implementation
- **Con:** Requires separate app, split UX for sync

### Phase 2: isomorphic-git (Production)
- Pure JS git implementation running in the WebView
- Replace `invoke("git_commit")` etc. with JS-side git operations
- **Pro:** Integrated UX, no external dependency
- **Con:** Slower on large vaults (~9200 files), limited advanced git features

### Phase 3: git2-rs / gitoxide (Future)
- Pure Rust git library compiled into the Tauri binary
- Best performance, no JS bridge overhead
- **Con:** Larger binary size, more integration work

## Next Steps

1. **Install iOS simulator runtime** — `xcodebuild -downloadPlatform iOS` (downloading ~7GB)
2. **Full Xcode build** — `npx tauri ios build --target aarch64-sim`
3. **Launch on iPad simulator** — `npx tauri ios dev`
4. **Test vault read/write** — open a vault, read/edit a note
5. **Test AI chat** — verify Anthropic API calls work from iOS WebView
6. **Evaluate touch UX** — identify layout issues on iPad screen size
7. **File Provider integration** — test opening vaults from Working Copy via iOS Files

## Prerequisites Installed

- Rust iOS targets: `aarch64-apple-ios`, `aarch64-apple-ios-sim`, `x86_64-apple-ios`
- Xcode 16.2 with iOS 18.3.1 simulator runtime (downloading)
- CocoaPods 1.16.2, xcodegen 2.45.3, libimobiledevice 1.4.0
- Tauri CLI 2.10.0 with iOS support