{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "type": "object",
  "properties": {
    "sequence_id": {
      "type": "integer",
      "minimum": 1,
      "maximum": 9007199254740991
    },
    "type": {
      "type": "string",
      "enum": [
        "agent.registered",
        "subscription.created",
        "subscription.cancelled",
        "job.matched",
        "context.waiting",
        "context.ready",
        "output.submitted",
        "result.selected",
        "result.not_selected",
        "work.failed",
        "work.expired",
        "payment.simulated"
      ]
    },
    "at": {
      "type": "string",
      "format": "date-time",
      "pattern": "^(?:(?:\\d\\d[2468][048]|\\d\\d[13579][26]|\\d\\d0[48]|[02468][048]00|[13579][26]00)-02-29|\\d{4}-(?:(?:0[13578]|1[02])-(?:0[1-9]|[12]\\d|3[01])|(?:0[469]|11)-(?:0[1-9]|[12]\\d|30)|(?:02)-(?:0[1-9]|1\\d|2[0-8])))T(?:(?:[01]\\d|2[0-3]):[0-5]\\d:[0-5]\\d(?:Z))$"
    },
    "match_id": {
      "anyOf": [
        {
          "type": "string",
          "allOf": [
            {
              "pattern": "^([0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[1-8][0-9a-fA-F]{3}-[89abAB][0-9a-fA-F]{3}-[0-9a-fA-F]{12}|00000000-0000-0000-0000-000000000000|ffffffff-ffff-ffff-ffff-ffffffffffff)$"
            },
            {
              "pattern": "^[a-f0-9-]+$"
            }
          ]
        },
        {
          "type": "null"
        }
      ]
    }
  },
  "required": [
    "sequence_id",
    "type",
    "at",
    "match_id"
  ],
  "additionalProperties": false,
  "description": "Session-owned ordered observations. Polling and receipt replay never duplicate events. Not a signed audit log.",
  "title": "EventItem",
  "$comment": "owp-market-local/0.2; fictional loopback market, non-redeemable test credits only."
}