Phase 5 Adr

Skill: Phase 5 — Architecture Decisions (ADR)

Purpose

Execute Phase 5: apply the architecture decision tree, create ADRs for every significant decision, generate C4 diagrams, and validate all ADRs before marking as Accepted.

When to use

• Phase 5 of the full 8-phase cycle
• When the user needs architecture guidance independently
• When designing a new module or refactoring an existing system

Decision Tree

Answer these questions in order to select the primary architectural pattern:

1. Single team or multiple autonomous teams?

   • Single → Modular Monolith
   • Multiple → Microservices

2. Does business complexity require a rich domain model?

   • Yes → Hexagonal Architecture / DDD
   • No → Layered Architecture

3. Is full state audit trail required?

   • Yes → Event Sourcing
   • No → Standard persistence

4. Are reads and writes radically different in volume?

   • Yes → CQRS
   • No → Standard CRUD

5. Are there distributed transactions across services?

   • Yes → Saga pattern (Orchestration or Choreography)
   • No → Local transactions

ADR Template (mandatory sections)

Every ADR must include:

# ADR-NNN: Short description of the decision

**Date:** YYYY-MM-DD
**Status:** Proposed | Accepted | Deprecated | Superseded
**Deciders:** Name, Role

## Context

[2-3 paragraphs: problem, constraints, why decide now]

## Decision

[Clear statement of the decision]

## Alternatives Considered

| Alternative | Pros | Cons | Why rejected |
|---|---|---|---|
| Option A | ... | ... | Rejected because [reason] |
| Option B | ... | ... | Rejected because [reason] |

## Consequences

**Positive:**
- [benefit 1]

**Negative:**
- [drawback 1] — mitigated by [mitigation]

## Compliance Impact

[State which standards affected, or confirm no impact]

Validation step

After generating each ADR, validate it:

node packs/enterprise-architecture-pack/validators/adr-validator/src/index.ts \
  --format=console docs/adr/ADR-NNN-title.md

Or in Antigravity Manager mode, use code execution:

import subprocess
subprocess.run(['node', '--experimental-strip-types', 
  'packs/enterprise-architecture-pack/validators/adr-validator/src/index.ts',
  '--format=console', 'docs/adr/ADR-001-isolation.md'])

Gate: If validation fails (any error-severity rule), fix the ADR and re-run. Only mark as Accepted after validation passes.

C4 Diagrams

Generate minimum:

• C4 L1 (System Context): External actors and systems
• C4 L2 (Container): Services, databases, message queues

Use Mermaid format (default) or PlantUML if requested.

Output artifacts

• docs/adr/ADR-001-*.md, ADR-002-*.md, ... (one per decision)
• C4 diagrams (inline in ADR or separate files)
• Artifact type in Manager mode: adr_document