Runtime Boundaries

CoreLayer enforces strict boundaries between components to ensure safety, reliability, and maintainability.

Boundary Model

Frontend (Browser/Webview)
  ║ Tauri IPC (typed, serialized)
  ╚═► Rust Backend
      ║ HTTP (localhost only)
      ╚═► Node.js Daemon
          ║ SDK interfaces
          ╚═► Shared Packages

Each boundary enforces:

• Type safety — typed interfaces between layers
• Isolation — components can't directly access each other's internals
• Communication protocol — well-defined APIs only

Frontend ↔ Rust

Communication uses Tauri's IPC mechanism:

• Commands are typed (TypeScript ↔ Rust)
• Serializes to JSON
• Async by default

Rust ↔ Daemon

Communication uses HTTP:

• Localhost only (not exposed to network)
• RESTful endpoints
• Streaming responses (SSE) for chat

Daemon ↔ Packages

Communication uses TypeScript imports:

• Direct function calls
• Shared type definitions
• Package boundaries enforced by module system

Daemon ↔ External Services

• AI Providers — HTTPS to cloud APIs
• MCP Servers — stdio or SSE protocol
• Databases — native drivers (better-sqlite3, pg)

Why Boundaries Matter

• Security — compromised frontend can't directly access database
• Reliability — daemon crash doesn't take down the frontend
• Testability — each layer can be tested independently
• Replaceability — swap storage or model providers without changing other layers

Next Steps

• System Overview — full architecture
• Security Model — safety details