> ## 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.

# Operating Lerian SPB

> Operating windows, certificate rotation, contingency handling, and the reconciliation model behind Lerian SPB.

Lerian SPB is built around two operational realities of the STR: it is open only within BACEN's operating windows, and settlement is always asynchronous. The rail persists everything before it dispatches, so no message is ever sent unrecorded.

## Operating windows

***

BACEN announces the STR operating-window grades (GEN0021), and you query them (STR0001). A submit attempted outside the window is rejected. A live schedule view shows the opening and closing times per reference date; the last announcement wins.

## Certificate rotation

***

The ICP-Brasil signing certificate pair is hot-reloaded with no restart. Rotating swaps the in-memory signing pointer and emits audit evidence; activating announces the new certificate to BACEN (GEN0006). Responses never expose the private key path or any key material, and certificate warnings surface in the readiness and summary views before expiry becomes a problem.

## Contingency and durability

***

* **Persist-before-send** guarantees no message is dispatched unrecorded.
* A **dispatch sweep** retries stuck outbound work.
* **Failed event deliveries** are retried manually, with a dead-letter path for deliveries that exhaust their retries.

## Reconciliation

***

Reconciliation is grained one case per operation-level settlement discrepancy. An operator resolves a case by recording an action against it, and terminal cases are locked so they cannot be reopened or re-actioned.

## Settlement invariants

***

Two invariants hold throughout:

* **A submit is dispatch, not confirmation.** `SUBMITTED` or `PENDING` means dispatch was accepted. Only the inbound R-leg yields `SETTLED` or `REJECTED`, carrying BACEN's settlement fields (for example `numCtrlSTR` and `sitLancSTR`) projected verbatim.
* **The rail is money-neutral.** It forwards declared amounts exactly and computes no position or balance — every accounting position lives in Midaz.