| name | ai-chat-app |
| description | Multi-provider AI chat application architecture with voice, memory, and usage tracking. Use when asked to build or modify an AI chat app, add model providers, implement voice features, manage memory systems, or track API usage costs. |
Multi-Provider AI Chat Application
Goal
Build and maintain a multi-provider AI chat application with voice, memory, and cost tracking.
Architecture Pattern
- Framework: Next.js 14 App Router
- Providers: OpenAI, Anthropic, Perplexity, Google, OpenRouter
- Persistence: Cookies (API keys), JSON files (usage + memory)
Key Architecture Decisions
Provider Routing
- Each provider has its own function returning
rawData for token extraction
- Token extraction differs by provider — normalize in a shared
extractTokenUsage function
- Strip
rawData before sending to client
Memory System
- JSON file persistence, lazy loaded
- 500 entry cap, auto-saved
- Memory context injected into every chat call
- Tools:
save_memory (AI saves) + recall_memory (AI retrieves)
Voice (Realtime)
- GPT-4o Realtime API for real-time voice
- Separate audio/text token pricing
calculateRealtimeCost() for accurate cost tracking
API Key Resolution
- Priority: environment variables first, then cookies
- Settings page saves keys as HTTP-only cookies
Cost Tracking
- Per-call token counting with provider-specific extraction
- Separate text vs. voice usage logging
- Real-time dashboard display
Common Build Issues & Fixes
| Issue | Fix |
|---|
ArrayBufferLike type error in voice | Cast as ArrayBuffer + new Float32Array() |
Union type on result.toolCalls | Type result as any |
| Realtime model constant in catch block | Use DEFAULT_REALTIME_MODEL constant |
| API key not found | Check env vars before cookies |
| Errors not visible in frontend | Check data.error before processing |
