---
title: "Tutorial: Read a Company Ledger"
description: "Check a supplied example, inspect its supplier claim, and produce a STIX bundle locally."
canonical: https://y2.dev/docs/ontology/tutorial/
---

Ontology & Fusion

# Tutorial: Read a Company Ledger

Check a supplied example, inspect its supplier claim, and produce a STIX bundle locally.

This lesson uses the repository's fictional company ledger. You will check its records, inspect a supplier claim, and produce a STIX bundle. The commands run locally and do not require a Y2 account or API key.

## Before you begin

You need a checkout of the Y2 platform repository, Bun, and jq. Run each command from the repository root in the same shell. The fixture is already supplied in `packages/ontology/v0/examples`. Its companies, identifiers, and source URLs are fictional.

### Check the supplied ledger

Set the fixture path:

```
ledger_fixture=packages/ontology/v0/examples/fictional-cyber-market.ndjson
```

Run the checker:

```
bun packages/ontology/src/cli.ts check "$ledger_fixture"
```

Expected output:

```
packages/ontology/v0/examples/fictional-cyber-market.ndjson: ok (22 lines)
```

The checker accepts all 22 records, their hashes, and their chain links.

### Read the current claims

A fold computes the current view from the recorded claims. Run this command to count the subjects and claims:

```
bun packages/ontology/src/cli.ts fold "$ledger_fixture" \
  | jq '{subjects: [.subjects[].subject.id], claims: (.claims | length)}'
```

Expected output:

```
{
  "subjects": ["sbj_issuer", "sbj_supplier", "sbj_portal"],
  "claims": 9
}
```

The subjects represent the company, its supplier, and its portal.

### Inspect the supplier claim

Select the claim with the `supplies` predicate:

```
bun packages/ontology/src/cli.ts fold "$ledger_fixture" \
  | jq '.claims[] | select(.predicate == "supplies") | {from, to, verification, evidence_refs}'
```

Expected output:

```
{
  "from": "sbj_supplier",
  "to": "sbj_issuer",
  "verification": "located",
  "evidence_refs": ["obv_filing"]
}
```

The direction runs from the supplier to the company. The claim cites `obv_filing` as its evidence. Its `located` state means that a retrieved page supports the link.

### Produce the STIX relationship

Project the ledger to STIX 2.1:

```
bun packages/ontology/src/cli.ts stix "$ledger_fixture" --scope tutorial \
  | jq '.objects[] | select(.type == "relationship" and .relationship_type == "supplies") | {relationship_type, confidence}'
```

Expected output:

```
{
  "relationship_type": "supplies",
  "confidence": 70
}
```

The STIX relationship preserves the supplier predicate and the claim's confidence. The export does not add new evidence.

## Continue with your own research

- [Record a claim with evidence](https://y2.dev/docs/ontology/how-to/record-evidence) in your workspace.
- [Read a previous ledger state](https://y2.dev/docs/ontology/how-to/read-at-a-point-in-time).
- [Export a workspace ledger](https://y2.dev/docs/ontology/how-to/export-and-verify).
- [Understand cyber-market fusion](https://y2.dev/docs/ontology/explanation/cyber-market-fusion).