If an Activity is submitted with a value in the id property, servers MUST ignore this and generate a new id for the Activity.

{
  "id": "urn:uuid:2bdc4682-308f-42ae-87cf-847f62f64e36",
  "type": "Behavior",
  "uuid": "2bdc4682-308f-42ae-87cf-847f62f64e36",
  "content": "If an Activity is submitted with a value in the id property, servers MUST ignore this and generate a new id for the Activity.\n",
  "context": [
    "https://www.w3.org/TR/activitypub/",
    {
      "name": "Client to server interaction"
    },
    {
      "name": "clients posting Activities to an actor's outbox"
    }
  ],
  "tag": [
    {
      "name": "ActivityPubServer",
      "id": "https://socialweb.coop/tag/ActivityPubServer"
    }
  ],
  "origin": {
    "source": "https://www.w3.org/TR/activitypub/",
    "section": {
      "id": "https://www.w3.org/TR/activitypub/#x6-client-to-server-interactions",
      "branch": [
        6
      ]
    },
    "selector": {
      "type": "TextQuoteSelector",
      "exact": "If an Activity is submitted with a value in the id property, servers MUST ignore this and generate a new id for the Activity.\n",
      "suffix": "Servers MUST return a 201 Created HTTP code, and unless the activity is transient, MUST include the new id in the Location header.\n"
    }
  },
  "@context": [
    "https://www.w3.org/ns/activitystreams",
    "https://socialweb.coop/ns/testing/context.json"
  ]
}