LucidPal
On-device AI calendar assistant for iOS — fully private, no cloud, powered by Qwen3.5.
What is LucidPal?
LucidPal is an on-device AI assistant that understands and manages your iOS calendar through natural language. Every word is processed locally on your iPhone — no data ever leaves the device.
| Feature | Description |
|---|---|
| 100% On-Device | All inference runs via llama.cpp on the Neural Engine. No API keys, no subscriptions, no internet required. |
| Calendar Integration | Create, update, delete and query events using plain English. Conflict detection included. |
| Siri Shortcuts | Ten built-in Siri intents let you manage your calendar, notes, contacts, and habits without ever opening the app. |
| Multi-Session | Full conversation history with named sessions, persisted locally across launches. |
Models
LucidPal ships with three GGUF model options, automatically selected based on device RAM:
| Model | Size | Min RAM | Recommended for |
|---|---|---|---|
| Qwen3.5 0.8B | 0.51 GB | 2 GB | Older iPhones with limited RAM |
| Qwen3.5 2B | 1.2 GB | 3 GB | Default — iPhone 12 / 13 and similar |
| Qwen3.5 4B | 2.5 GB | 5 GB | iPhone 14 Pro / 15 / 16 and newer |
All three models run natively via llama.cpp with Metal GPU acceleration.
Tech Stack
| Layer | Technology |
|---|---|
| Language | Swift 5.10 + SwiftUI |
| LLM Runtime | llama.cpp (C FFI via Swift actor) |
| Calendar | EventKit (wrapped in CalendarService) |
| Speech | AVFoundation + SFSpeechRecognizer |
| Siri | AppIntents framework |
| Persistence | Custom JSON session store |
| Testing | XCTest with full mock infrastructure |