# Phase 02 Overview: Backend Orchestration Engine

## Objective
Implement deterministic runtime behavior for stage transitions, routing, filtering, assignment, live cursor control, and notification/audit emission.

## In Scope

- transition engine
- routing engine
- filtering orchestration (gates + AI + manual queue)
- assignment orchestration with coverage guarantees
- live cursor and cohort window controls
- event and audit emission

## Out of Scope

- full admin UI and participant UI implementation

## Exit Criteria

1. Runtime contracts implemented and integration-tested.
2. Determinism and idempotency guarantees proven for critical mutations.
3. Mandatory phase gates complete with test evidence.