{
  "description": "Group-apps registry vectors: which trusted first-party apps a group chat has added. The registry is fold state from wire events in the group's own encrypted log — the server never learns which app was added. Source of truth: web/static/apps.js (the groupapps system app).",
  "app": "groupapps",
  "source": "web/static/apps.js (installsApp — one registry for every shared place; this file pins its groupapps event family)",
  "state_shape": {
    "apps": [
      {
        "id": "string (the added app's name, e.g. \"todo\")",
        "by": "string (sender name)",
        "ts": "number (epoch ms)"
      }
    ]
  },
  "notes": [
    "The item id IS the app name, so a duplicate add (any member, any refold) is a no-op and a remove needs no lookup.",
    "Unknown app names fold into state unchanged in shape — clients filter to registered, groupCapable apps at READ time (groupAppsFor), so old and new clients converge on the same log.",
    "Chat projection: the group fold prefixes the actor's name onto the projection text, so the rendered action line is e.g. \"Ana added To-do to this chat\". The expected_chat_projection below is the raw groupFeedMessage() output, pre-prefix — same convention as todo.json (whose companion app projects via chatMessage instead).",
    "An app's own events posted into a group thread fold with the app's ordinary vectors (todo.json etc.) — same events, same reducer, keyed by the group thread instead of the personal one."
  ],
  "vectors": [
    {
      "name": "groupapps_add",
      "description": "A member adds a trusted app to the group.",
      "event": {
        "type": "groupapps.add",
        "app": "todo",
        "name": "Ana",
        "ts": 1700000000000
      },
      "expected_state_update": {
        "apps": [
          {
            "id": "todo",
            "by": "Ana",
            "ts": 1700000000000
          }
        ]
      },
      "expected_chat_projection": {
        "text": "added To-do to this chat",
        "action": true
      }
    },
    {
      "name": "groupapps_add_duplicate",
      "description": "Re-adding an already-added app is a no-op (idempotent by app name).",
      "event": {
        "type": "groupapps.add",
        "app": "todo",
        "name": "Bob",
        "ts": 1700000005000
      },
      "initial_state": {
        "apps": [
          {
            "id": "todo",
            "by": "Ana",
            "ts": 1700000000000
          }
        ]
      },
      "expected_state_update": {
        "apps": [
          {
            "id": "todo",
            "by": "Ana",
            "ts": 1700000000000
          }
        ]
      },
      "note": "The original add's attribution is kept — a duplicate never rewrites by/ts."
    },
    {
      "name": "groupapps_remove",
      "description": "A member removes an added app from the group.",
      "event": {
        "type": "groupapps.remove",
        "app": "todo",
        "name": "Ana",
        "ts": 1700000010000
      },
      "initial_state": {
        "apps": [
          {
            "id": "todo",
            "by": "Ana",
            "ts": 1700000000000
          }
        ]
      },
      "expected_state_update": {
        "apps": []
      },
      "expected_chat_projection": {
        "text": "removed To-do from this chat",
        "action": true
      }
    },
    {
      "name": "groupapps_add_malformed",
      "description": "An add with no app name (malformed or hostile) folds to a no-op, never a crash.",
      "event": {
        "type": "groupapps.add",
        "name": "Mallory",
        "ts": 1700000020000
      },
      "initial_state": {
        "apps": []
      },
      "expected_state_update": {
        "apps": []
      }
    },
    {
      "name": "groupapps_remove_missing",
      "description": "Removing an app that isn't added (a cancel racing a remove, a refold) is a no-op.",
      "event": {
        "type": "groupapps.remove",
        "app": "todo",
        "name": "Ana",
        "ts": 1700000030000
      },
      "initial_state": {
        "apps": []
      },
      "expected_state_update": {
        "apps": []
      }
    }
  ]
}