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Architecture Review Checklist (ADR Template)

Purpose

Use this checklist for every architecture change proposal to enforce 02-island-boundaries-and-performance.md and prevent service/package sprawl.

How To Use

  1. Copy this file into a dated ADR file, for example docs/migration/adr/ADR-2026-02-07-example.md.
  2. Fill every field with Pass, Partial, or Fail.
  3. Attach evidence (doc sections, diagrams, API contracts, benchmarks).
  4. Do not approve implementation until all mandatory gates pass.

ADR Metadata

Field Value
ADR ID
Date
Status (Proposed/Accepted/Rejected/Superseded)
Author(s)
Reviewer(s)
Related Ticket(s)
Affected Island(s)
Related Docs

Change Summary

Item Value
Decision statement
Problem being solved
Option selected
Rejected options
Rollout scope

Gate A: Deployable Boundary (Mandatory)

Check Result Evidence Notes
Total Day 1 deployables remain <= 5
If adding a new app, at least 2 split criteria are met (security boundary, scaling profile, release cadence, data ownership)
If criteria are not met, change stays inside existing island

Gate B: Package Extraction (Mandatory)

Check Result Evidence Notes
Internal shared package count remains <= 3
New package is reused by at least 2 islands
New package API is expected stable for >= 6 months
Package does not contain app-specific ORM entities/workflows
No shared mutable domain bundle is introduced (Article, Order, Vehicle, etc.)

Gate C: Data Ownership And Contracts (Mandatory)

Check Result Evidence Notes
Each island owns its schema and migrations
No cross-island direct DB queries/writes
Sync API contracts are documented for low-latency reads
Async contracts are documented for write propagation
Outbox/inbox and idempotency design is defined

Gate D: Performance Plan (Mandatory)

Check Result Evidence Notes
Read model/projection strategy exists for impacted high-volume paths
Stock availability path has explicit p95 target
Vehicle fitment path has explicit p95 target
Wheel-set composition path has explicit p95 target
Capacity plan for peak import/export windows is documented

Gate E: Operability And Resilience (Mandatory)

Check Result Evidence Notes
Queue topology documented (high-priority, bulk, DLQ)
Retry/backoff policy defined per connector flow
Checkpoint/watermark strategy exists for resumable jobs
Structured logs, metrics, and alerts defined
Failure replay/runbook documented

Decision Outcome

Item Value
Outcome (Approve/Approve with conditions/Reject)
Blocking conditions
Follow-up actions
Target completion date

Post-Implementation Review

Check Value
Actual p95 metrics vs planned
Incident count during rollout
Contract-break incidents
Needed ADR updates