Rivet Agent Isolation

Rivet Agent Isolation

Note: This document is superseded by Rivet Actor Model which contains the full implementation. This document covers the conceptual model of per-user isolation.

Overview

Each WhatsApp user gets an isolated Rivet actor — a durable, self-contained unit of execution that owns its own state, tools, and conversation history. There is zero shared state between users.

Isolation Model

graph TB
    subgraph "Message Ingestion"
        MSG[Incoming Message]
        PHONE[Phone Number ID]
    end

    subgraph "Rivet Orchestration"
        LOOKUP{Actor exists?}
    end

    subgraph "Rivet Cluster"
        A1["Actor +94771234567<br/>(isolated)"]
        A2["Actor +94719876543<br/>(isolated)"]
        A3["Actor +94765555555<br/>(isolated)"]
    end

    MSG --> PHONE
    PHONE --> LOOKUP
    LOOKUP -->|Yes| A1
    LOOKUP -->|Yes| A2
    LOOKUP -->|No| A3

    style A1 fill:#c8e6c9
    style A2 fill:#c8e6c9
    style A3 fill:#c8e6c9

Why Actor Isolation?

Security

• User data is never visible to other users
• No cross-user state leakage
• Each user has their own rate limit, abuse tracking, injection violation count

State Management

• Each actor owns its conversation history
• Cart state is per-user
• Preferences are per-user
• Durable state survives sleep/wake/restarts

Concurrency

• Rivet serializes on_message() per actor — no race conditions
• No shared resources to protect
• No locks needed

Scalability

• Actors distribute across cluster automatically
• No sticky sessions required
• Horizontal scaling by adding Rivet nodes

Actor State

stateDiagram-v2
    [*] --> Created: First message
    Created --> Running: on_init() complete
    Running --> Active: Processing messages
    Active --> Idle: 5 min no activity
    Idle --> Active: New message arrives
    Idle --> Terminated: 1 hr idle
    Active --> Terminated: User blocks/deletes

    note right of Active
        Isolated state
        Per-user conversation
        Per-user tools
    end note

Resource Allocation

Integration with AgentOS

flowchart LR
    A[WhatsApp Webhook] --> B[FastAPI Gateway]
    B --> C[Rivet get_actor]
    C --> D[Rivet Actor]
    D --> E[AgentOS V8 Isolate]
    E --> F[Pi Agent Core]
    F --> G[Shopify MCP Tools]
    F --> H[Rivet Durable State]

Each actor contains:

• An AgentOS V8 isolate (sandboxed OS)
• A Pi Agent Core instance (LLM orchestration)
• Registered Shopify MCP tools
• Durable state (conversation + security + user state)

What Rivet Handles

See Also

• Rivet Actor Model — Full implementation with code
• Agent Lifecycle — Message flow
• AgentOS Configuration — Sandbox details
• Concurrency & Security — Rate limiting, injection prevention