Phase 3 — Operation Plane (Plan)

Unit type: Phase Epic: lattice-platform-development (lattice-platform-agentic-development-v0.2.md) Unit ID: phase-3 Status: Rolling-wave placeholder — see phase-3-status.md Sketch: phase-3-sketch.md Depends on: Phase 2 exit gate Full VP-level expansion scheduled at: P2.11.4

1. Scope

Projections stay fresh, tanks respond, values flow back. Milestones M7 (projections live), M8 (tanks respond), M9 (write-back).

Authoritative slice-level detail: epic Part 7. Hard gate restated from the epic: no C-09 slice starts until C-07 reconciliation (P3.1.7) is green for a full week of nightly runs, injected-divergence scenario included.

2. Documentation obligations — docs/architecture (known now)

Document Change Producing slice
docs/architecture/data-architecture.md Add valid-time cold partitioning and archive dataset conventions P3.5.5
Runbook: restore-from-backup / restore-from-bundle New — place under docs/operator/ (existing home for operational runbooks, e.g. release-stack-reference.md), not a new top-level docs/runbooks/ P3.5.3
Full doc table Deferred P2.11.4

3. README obligations (known now)

New subproject Track
platform/projection-engine C-07
platform/behaviour-engine C-09
platform/writeback C-10

4. solution-design-specification.md delta plan (known now)

SDS section Change Note
§7 Robustness Design Add projection freshness contracts, aggregate lease/fencing, write-back conflict handling (never last-write-wins) Full table at P2.11.4
§5.1 Deployment Topology Add role-profiled HA posture (≥2 control, ≥3 edge, partitioned behaviour with failover) P3.5.1

5. Phase gate checklist

Standard per epic Part 12.

6. Dependencies

Depends on Phase 2 exit gate. Blocks Phase 4 (maturity work measures against this phase’s benchmarks, per P3.6.1–P3.6.3).