Position in workflow: Terminal activity of Define Architecture (DTA) — order 20 of 20. Run only after all prior DTA domain activities are complete (DTA-02 through DTA-17, and when applicable DTA-19 AI Agent Architecture and DTA-20 MCP Architecture).

Write SAO.md (System Architecture Overview)

Objective

Compile all architectural decisions from DTA-02 through DTA-17 (and optionally DTA-19 and DTA-20 if applicable) into a single, authoritative document: docs/architecture/SAO.md.

Process

1. Gather All Decisions

Collect recorded decisions from each domain activity:
- DTA-02: Application Blocks
- DTA-03: Integration & API Design
- DTA-04: Code Organization
- DTA-05: Data Architecture
- DTA-06: Test Strategy
- DTA-07: Performance & Scalability
- DTA-08: Error Handling & Resilience
- DTA-09: Infrastructure
- DTA-10: CI/CD Pipeline
- DTA-11: Release & Rollback
- DTA-12: Observability
- DTA-13: Config & Secrets
- DTA-14: Security
- DTA-15: Backup & Recovery
- DTA-16: Developer Experience
- DTA-17: Documentation Strategy
- DTA-19: AI Agent Architecture (if applicable)
- DTA-20: MCP Architecture (if applicable)

2. Write SAO.md

Structure — add sections 17 and 18 after section 16:

## 16. Documentation Strategy
[Decision from DTA-17]

## 17. AI Agent Architecture
[Decision from DTA-19 — skip section if no in-app agent]

## 18. MCP Architecture
[Decision from DTA-20 — skip section if no MCP interface]

3. Skill Gap Analysis

Compile coverage reports from all domain activities into a single matrix:

Domain                   | Covered Skills     | Gaps
Application Blocks       | [list]             | [list]
...
AI Agent Architecture    | [list]             | [list]
MCP Architecture         | [list]             | [list]

4. Review with User

Present SAO.md for review. Get explicit approval before proceeding to Bootstrap Project.

5. Post-Implementation Updates

The SAO is a living document. During and after implementation, update it with critical discoveries, retrospective corrections, and recurring patterns. Each update should reference the original DTA decision.

Deliverables

• SAO.md written at docs/architecture/SAO.md
• All domain decisions (16 core + up to 2 optional: AI Agent, MCP) compiled
• Skill coverage report included
• Key decisions summary with rationale
• User approval obtained
• Ready to proceed to Define Software Process (DSP). DSP requires SAO.md to generate the AI IDE configuration — run DSP before BSP.

When ESM, DTA, DSP, and BSP are all complete, proceed to BSP-08 for the Construction Handoff and mode selection.