# org.cairnsproto.draft.seen

> A timekeeper's record of which Cairns records it first saw, across every project, in the rounds after afterRound through beaconRound. Published at the timekeeper's cadence and skipped when nothing new was seen.

- Kind: record
- Record key: tid
- Authority: draft.cairnsproto.org
- Lexicon: 1
- Published by [cairnsproto.org](https://lexicon.garden/identity/did:plc:np7ezqujtsry4bkogisaabul), the NSID's authority

## Links

- [Documentation](https://lexicon.garden/lexicon/did:plc:np7ezqujtsry4bkogisaabul/org.cairnsproto.draft.seen)
- [Schema JSON](https://lexicon.garden/lexicon/did:plc:np7ezqujtsry4bkogisaabul/org.cairnsproto.draft.seen/schema.json)
- [Analytics](https://lexicon.garden/lexicon/did:plc:np7ezqujtsry4bkogisaabul/org.cairnsproto.draft.seen/analytics)

## Record (`org.cairnsproto.draft.seen`)

Type: record · key tid

### Properties

- `afterRound` (integer): The window starts after this round: the previous record's beaconRound, or 0 for a timekeeper's first record.
  - Constraints: minimum: 0
- `beaconRound` (integer, required): drand quicknet round that closes the window.
  - Constraints: minimum: 1
- `createdAt` (string · datetime, required)
- `externalAnchor` (ref)
  - Reference: `#externalAnchor`
- `firstSeen` (ref): The leaves under firstSeenRoot.
  - Reference: `org.cairnsproto.draft.defs#external`
- `firstSeenRoot` (ref, required): RFC 6962 Merkle root over each record first seen in the window: its URI, a zero byte, and its binary CID.
  - Reference: `org.cairnsproto.draft.defs#hash`
- `previous` (ref)
  - Reference: `com.atproto.repo.strongRef`

## #externalAnchor (`org.cairnsproto.draft.seen#externalAnchor`)

Type: object

Where firstSeenRoot was also published outside ATProto.

### Properties

- `reference` (string, required)
  - Constraints: maxLength: 2048
- `system` (string, required)
  - Constraints: maxLength: 128

## Schema

```json
{
  "$type": "com.atproto.lexicon.schema",
  "defs": {
    "externalAnchor": {
      "description": "Where firstSeenRoot was also published outside ATProto.",
      "properties": {
        "reference": {
          "maxLength": 2048,
          "type": "string"
        },
        "system": {
          "maxLength": 128,
          "type": "string"
        }
      },
      "required": [
        "system",
        "reference"
      ],
      "type": "object"
    },
    "main": {
      "description": "A timekeeper's record of which Cairns records it first saw, across every project, in the rounds after afterRound through beaconRound. Published at the timekeeper's cadence and skipped when nothing new was seen.",
      "key": "tid",
      "record": {
        "properties": {
          "afterRound": {
            "description": "The window starts after this round: the previous record's beaconRound, or 0 for a timekeeper's first record.",
            "minimum": 0,
            "type": "integer"
          },
          "beaconRound": {
            "description": "drand quicknet round that closes the window.",
            "minimum": 1,
            "type": "integer"
          },
          "createdAt": {
            "format": "datetime",
            "type": "string"
          },
          "externalAnchor": {
            "ref": "#externalAnchor",
            "type": "ref"
          },
          "firstSeen": {
            "description": "The leaves under firstSeenRoot.",
            "ref": "org.cairnsproto.draft.defs#external",
            "type": "ref"
          },
          "firstSeenRoot": {
            "description": "RFC 6962 Merkle root over each record first seen in the window: its URI, a zero byte, and its binary CID.",
            "ref": "org.cairnsproto.draft.defs#hash",
            "type": "ref"
          },
          "previous": {
            "ref": "com.atproto.repo.strongRef",
            "type": "ref"
          }
        },
        "required": [
          "beaconRound",
          "firstSeenRoot",
          "createdAt"
        ],
        "type": "object"
      },
      "type": "record"
    }
  },
  "id": "org.cairnsproto.draft.seen",
  "lexicon": 1
}
```