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The Block

An ALX Block is a data object with five protocol fields: application-defined JSON content, the parentHashes of its direct parent Blocks, two deterministic hashes, and a protocolVersion. Conforming implementations recompute both hashes from content and parentHashes and compare them with the recorded values.

The Five Fields​

Block defines each field and the parent normalization rules.

type Block = {
  blockHash: string;
  contentHash: string;
  parentHashes: string[];
  content: unknown;
  protocolVersion: "1";
};

A Complete Block​

A root Block declares no parents; createBlock(content, []) returns the root Block below. The derived Block lists the policy's blockHash in parentHashes.

Root Block
{
  "blockHash": "0x6e4a0ec5756a4569b4bfe1fca097a70fb151da446fb26f138f3edce1958a9e37",
  "contentHash": "0xf90f01822677e747de0a7173c74fdb0af4079f983489931cec878e3ef4b02f96",
  "parentHashes": [],
  "content": {
    "type": "reference-document",
    "title": "Information Security Policy",
    "uri": "https://example.org/policies/security.pdf",
    "version": "3.1",
    "publishedAt": "2026-05-10"
  },
  "protocolVersion": "1"
}
Derived Block
{
  "blockHash": "0xa0c9a3ac4d1cb0a27047ba674befce43f6049c98719722965607798aa507b746",
  "contentHash": "0x3fb15a5557b2009dfe24878fffda0ee091e41ec89e78dfa96be63d621c497b5f",
  "parentHashes": [
    "0x6e4a0ec5756a4569b4bfe1fca097a70fb151da446fb26f138f3edce1958a9e37"
  ],
  "content": {
    "type": "agent-output",
    "task": "Summarize the security review",
    "result": "The review identified three high-priority findings.",
    "model": "application-defined",
    "createdAt": "2026-07-28T14:30:00Z"
  },
  "protocolVersion": "1"
}

Content Examples​

ALX treats content as opaque application data. The examples below show content payloads only.

Market inputs and an application-defined assessment. Parent Blocks: the market dataset, a prior analysis, the model output, and the analyst review.

{
  "type": "market-analysis",
  "symbol": "EXMPL",
  "observationDate": "2026-07-28",
  "inputs": {
    "price": 182.41,
    "revenueGrowth": 0.34
  },
  "assessment": "positive"
}

When to Create a Block​

Create a Block when JSON-serializable content needs deterministic identity, declared parent relationships, or both. A Block with an empty parentHashes array is a root Block; a Block with parents extends a derivation Graph.