companion-architecture

You are an expert in designing multi-tenant architectures for AI companions, focusing on isolation, security, and scalability for production companion services.

Companion System Architecture

Core Domain Model

// src/domain/companion.ts
export interface Companion {
  id: string;
  name: string;
  description: string;
  ownerId: string; // Organization or user that owns this companion
  
  // Companion personality and behavior
  personality: {
    traits: string[];
    tone: "professional" | "friendly" | "casual" | "formal";
    responseStyle: "concise" | "detailed" | "conversational";
  };
  
  // AI Configuration
  aiConfig: {
    model: string;
    temperature: number;
    maxTokens: number;
    systemPrompt: string;
    knowledgeCutoff?: string;
  };
  
  // Capabilities and permissions
  capabilities: {
    canAccessInternet: boolean;
    canExecuteCode: boolean;
    canAccessFiles: boolean;
    allowedTools: string[];
    memoryRetentionDays: number;
    maxMemoriesPerUser: number;
  };
  
  // Multi-tenancy
  tenancy: {
    isolationLevel: "strict" | "shared" | "hybrid";
    dataResidency?: string; // Geographic location for data
    encryptionKeyId?: string; // For tenant-specific encryption
  };
  
  // Usage and limits
  limits: {
    maxDailyInteractions: number;
    maxConcurrentSessions: number;
    maxMemoryStorage: number; // In MB
    rateLimitPerMinute: number;
  };
  
  // Lifecycle
  status: "active" | "paused" | "archived" | "deleted";
  version: string;
  createdAt: Date;
  updatedAt: Date;
  lastActiveAt?: Date;
}

// User-Companion relationship
export interface CompanionUser {
  companionId: string;
  userId: string;
  
  // Relationship metadata
  relationship: {
    firstInteraction: Date;
    lastInteraction: Date;
    interactionCount: number;
    trustLevel: number; // 0-100
  };
  
  // User-specific companion settings
  preferences: {
    nickname?: string;
    preferredLanguage?: string;
    timezone?: string;
    customSettings?: Record<string, any>;
  };
  
  // Access control
  permissions: {
    canRead: boolean;
    canWrite: boolean;
    canDelete: boolean;
    isBlocked: boolean;
  };
  
  // Usage tracking
  usage: {
    tokensUsed: number;
    memoriesCreated: number;
    lastMemoryAt?: Date;
  };
}