Architecture

LARouter is a monorepo with three main components: a Hono-based API server, a React WebUI dashboard, and an MCP tool server.

System Diagram

Request Flow

When a request arrives at /v1/chat/completions:

1. Auth Middleware — Validates bearer token, resolves project context
2. Classifier — Heuristic analysis → confidence check → optional AI fallback
3. Tier Router — Maps the classified tier to a specific model from the project's routing policy
4. Executor — Sends the request to the selected provider (local or cloud)
5. Streaming — If SSE, streams chunks back to the client in real-time
6. Token Tracker — Records usage (input/output tokens, cost, project, model)

Directory Structure

LARouter/
├── backend/                ← Hono API server (Bun runtime)
│   ├── src/
│   │   ├── index.ts        ← Entry point + graceful shutdown
│   │   ├── server.ts       ← Hono routes + proxy handler
│   │   ├── classifier.ts   ← Heuristic request classifier
│   │   ├── ai-classifier.ts← AI fallback classifier
│   │   ├── router.ts       ← Tier → model mapping
│   │   ├── executor.ts     ← Provider execution + escalation
│   │   ├── token-tracker.ts← Per-project billing
│   │   ├── projects.ts     ← Multi-tenant project manager
│   │   ├── model-manager.ts← Download + llama-server lifecycle
│   │   ├── mcp-server.ts   ← MCP tool server
│   │   ├── cli.ts          ← Admin CLI
│   │   ├── auth.ts         ← Bearer token middleware
│   │   ├── config.ts       ← Configuration loader
│   │   ├── models.ts       ← Provider registry
│   │   ├── logger.ts       ← SQLite logging
│   │   └── streaming.ts    ← SSE passthrough
│   └── config/
│       └── default.json    ← Default tier mappings
│
├── frontend/               ← React WebUI dashboard
│   ├── src/
│   │   ├── main.tsx        ← App entry + router + sidebar
│   │   ├── pages/          ← Overview, Models, Projects, Usage, Settings
│   │   ├── lib/            ← API client
│   │   └── styles.css      ← Design tokens + components
│   └── vite.config.ts
│
├── documents/              ← This documentation site
│   ├── docs/               ← Markdown source files
│   └── website/            ← Docusaurus 3.10 config
│
└── models/                 ← Downloaded model files (gitignored)

Ports

Service	Port	Description
Backend API	18790	Hono server — proxy + admin API
Frontend WebUI	5174	Vite dev server — React dashboard
MCP SSE	18791	MCP tool server (SSE transport)
llama-server	8001+	Local model inference (auto-assigned)
Docs	3002	Docusaurus documentation site