> ## Documentation Index
> Fetch the complete documentation index at: https://docs.lerian.studio/llms.txt
> Use this file to discover all available pages before exploring further.

# Integrating with Lerian STA

> What Lerian STA emits — the per-transfer terminal events over a transactional outbox on an audit and a signed business channel, the claim-check carried on inbound success, and the STA-to-consumer-to-Midaz reconciliation chain.

Lerian STA is event-first at its edges. It publishes a **terminal event per transfer** through a **transactional outbox**, so an event reaches consumers if and only if the transfer's state change has committed. Consumers are the **source-product** services that own the files Lerian STA delivers.

## Event channels

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Lerian STA publishes on two channels:

* An **audit channel**, keyed by the file's **source product**, carrying inbound-success and inbound-failure facts for observability and reconciliation.
* A **signed business channel**, keyed by **direction and source product**, for external product consumers. Its terminal event types are `sta.transfer.accepted`, `sta.transfer.rejected`, `sta.transfer.inconsistent`, `sta.transfer.canceled`, and `sta.transfer.download_finished`.

Each event carries an enumerated **error code** and, on inbound success, the **claim-check**.

## The claim-check

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On a completed inbound download, Lerian STA emits its terminal **download-finished** event, keyed by the file's source product. The event carries a **claim-check** — the object key, the SHA-256, the size, the file name, and the document type — but not the bytes themselves.

The consuming domain product subscribes to its own key, fetches the durable artefact by its object key, **re-verifies** the SHA-256, and reconciles the result into the **Midaz** ledger. Lerian STA is the transport and integrity boundary; the consuming product owns the ledger posting.

## Midaz boundary

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Lerian STA does not write to Midaz itself. It delivers the file and the claim-check; the consuming product — for example, **Lerian SISBAJUD** for judicial asset-order files — performs the ledger reconciliation. This keeps Lerian STA a pure transport-and-integrity layer, independent of any one file's business meaning.

## Integration conventions

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* **Commit-coupled events.** Every event flows through the transactional outbox, so it is published only when its transfer's state change has committed.
* **Claim-check, not payload.** Consumers receive a reference to the durable artefact, fetch it, and re-verify its SHA-256 before acting on it.
* **Keyed subscription.** Each source-product consumer subscribes only to its own key, so a discovered file reaches exactly the product that owns it.