{
  "$schema": "https://nuncaeslupus.github.io/drawspec/schema/drawspec-v1.schema.json",
  "version": 1,
  "kind": "flow",
  "title": "The library's lending system in context",
  "description": "A system context diagram in the C4 style: the lending system in the middle, the people who use it drawn as people, and the systems run by other organisations greyed and named in the key — one class, since only the grey needs explaining.",
  "nodes": [
    {
      "id": "member",
      "text": "Library member\nborrows and reserves books",
      "role": "person"
    },
    {
      "id": "staff",
      "text": "Branch staff\nissue, return and fine",
      "role": "person"
    },
    {
      "id": "lending",
      "text": "Lending system\nloans, reservations, fines, the catalogue",
      "role": "emphasis"
    },
    {
      "id": "identity",
      "text": "Council sign-in\nresidents' accounts",
      "class": "external"
    },
    {
      "id": "payments",
      "text": "Card payments\npays fines online",
      "class": "external"
    },
    {
      "id": "mail",
      "text": "Email service\nsends due-date reminders",
      "class": "external"
    }
  ],
  "edges": [
    {
      "from": "member",
      "to": "lending",
      "label": "reserves"
    },
    {
      "from": "staff",
      "to": "lending",
      "label": "issues"
    },
    {
      "from": "lending",
      "to": "identity",
      "label": "sign-in"
    },
    {
      "from": "lending",
      "to": "payments",
      "label": "fines"
    },
    {
      "from": "lending",
      "to": "mail",
      "label": "reminders"
    }
  ],
  "classes": [
    {
      "id": "external",
      "text": "Run by another organisation"
    }
  ]
}