Tier 03 · Architect · Lab 26

Implement a Settlement State Machine

Drive the MNE settlement state machine through two-phase issuance with append-only ledger integrity.

Architect Tier — MNE Settlement State Machine

PENDINGCURRENT

Settlement quote received, awaiting validation

VALIDATED

Execution receipt verified, ready for prepare

PREPARED

Phase 1: Lock acquired, DIU reserved

COMMITTED

Phase 2: DIU issued, ledger entry written

ROLLED_BACK

Timeout or failure, locks released

Valid Transitions (forward edges only)

PENDINGVALIDATED(receipt_verified)Validation

VALIDATEDPREPARED(prepare_commit)Phase 1

PREPAREDCOMMITTED(commit)Phase 2

PREPAREDROLLED_BACK(timeout)Rollback

PENDINGROLLED_BACK(invalid_receipt)Rollback

Lab progress

✓

Spec

Execute

Submit