Causal Receipts

CausalReceipt is lazily’s generic outcome projection for commands and effect requests keyed by a stable causation_id.

It is intentionally not a transport ACK. observed and accepted are non-terminal receipt outcomes; they can record that a peer saw or queued work. applied and rejected are terminal outcomes. Domain-specific facts may refine those terminal outcomes, but they should not invent a delivery-ACK authority.

{
  "description": "Causal receipts fold by causation id and generation. observed/accepted are non-terminal; applied/rejected are terminal; stale generations are ignored by the current projection.",
  "protocol_version": 1,
  "kind": "Receipt",
  "model": "CausalReceipt",
  "assertions": {
    "receipt_count": 4,
    "current_generation": 7,
    "causation_id": "patch-123",
    "terminal_outcome": "applied",
    "stale_receipt_ids": ["receipt-stale"],
    "nonterminal_outcomes": ["observed", "accepted"]
  },
  "wire": {
    "CausalReceipts": {
      "receipts": [
        {
          "receipt_id": "receipt-observed",
          "causation_id": "patch-123",
          "observer": "editor",
          "generation": 7,
          "outcome": "observed",
          "reason": null,
          "payload_hash": null
        },
        {
          "receipt_id": "receipt-accepted",
          "causation_id": "patch-123",
          "observer": "editor",
          "generation": 7,
          "outcome": "accepted",
          "reason": null,
          "payload_hash": null
        },
        {
          "receipt_id": "receipt-applied",
          "causation_id": "patch-123",
          "observer": "editor",
          "generation": 7,
          "outcome": "applied",
          "reason": null,
          "payload_hash": "sha256:2cf24dba5fb0a30e26e83b2ac5b9e29e1b161e5c1fa7425e73043362938b9824"
        },
        {
          "receipt_id": "receipt-stale",
          "causation_id": "patch-123",
          "observer": "editor",
          "generation": 6,
          "outcome": "rejected",
          "reason": "stale generation",
          "payload_hash": null
        }
      ]
    }
  }
}

The normative field list and projection rules live in protocol.md § Causal Receipts. The schema is schemas/receipts.json.