Phase 12 — Failure Lab & End-to-End Demonstrations

[aaqib-hafeez-khan-in]

Parent epic: #3

Objective

Create reproducible scenarios that demonstrate LedgerFlow's correctness, reliability, and recovery behavior end to end.

Scope

Demonstrate at minimum:

• Duplicate transaction request
• Duplicate event delivery
• Concurrent duplicate requests
• Failed processing followed by retry
• Permanently failed transaction routed to dead letter
• Missing event
• Duplicate external settlement record
• Ledger amount mismatch
• Partial settlement failure
• Successful recovery after transient infrastructure failure

Acceptance criteria

• Each scenario is reproducible locally.
• Expected behavior and invariants are documented.
• Scenarios produce observable evidence through tests, logs, telemetry, or API responses.
• Recovery scenarios demonstrate that financial effects are not duplicated.
• The final documentation ties the scenarios back to the architectural decisions in the epic.

Delivery

Implement as a focused PR linked back to #3.