Creating a Contract

contract_name: order_fulfillment
version: 1
description: E-commerce order fulfillment workflow

# Entry points - where threads can start
entry_points:
  - order_placed

# Parties involved in the workflow
parties:
  - merchant
  - logistics

# Steps in the workflow
steps:
  - id: order_placed
    owner: merchant
    type: managed
    timeout: 5m
    business_context:
      required:
        - order_id
        - product_id
        - quantity
      optional:
        - customer_notes

  - id: inventory_checked
    owner: merchant
    type: managed
    timeout: 1m
    business_context:
      required:
        - in_stock
        - warehouse_id

  - id: shipment_created
    owner: logistics
    type: managed
    timeout: 24h
    business_context:
      required:
        - tracking_number
        - carrier_name

# Transitions define valid step flows
transitions:
  - from: order_placed
    to:
      - inventory_checked

  - from: inventory_checked
    to:
      - shipment_created
      - order_cancelled

# Terminal steps - where threads can end
terminal_steps:
  - order_delivered
  - order_cancelled

# Thread-level timeout
max_duration: 7d

const thread = await connection.start('order_fulfillment', 'merchant');

// Contract validates this is a valid entry point
// and checks for required fields
await thread.step('order_placed')
  .addContext({ 
    order_id: order.id,        // required by contract
    product_id: order.productId, // required by contract
    quantity: order.quantity    // required by contract
  })
  .success();

// Use latest version (recommended)
const thread = await connection.start('order_fulfillment', 'merchant');

// Use specific version
const thread = await connection.start('order_fulfillment:2', 'merchant');