Target Architecture Design

Design a target (to-be) architecture that addresses identified gaps and risks while preserving working components of the existing system.

Argument Parsing

Parse $ARGUMENTS for the following flags:

Flag	Required	Default	Description
--project	Yes	—	Project name
--output-dir	No	artifacts/brownfield/<project>	Output directory

If --project is missing, output usage instructions and stop.

Upstream Artifact Loading

Read upstream artifacts from the output directory:

1. Required: Read <output-dir>/AS_IS_SYSTEM_MODEL.md — current architecture baseline
2. Required: Read <output-dir>/ARCH_GAPS_AND_RISKS.md — gaps to address
3. Optional: Read <output-dir>/REVERSE_PRD.md — feature inventory to preserve
4. Optional: Read <output-dir>/REVIEW_BRIEF.md — review goals
5. Optional: Read <output-dir>/ALIGNMENT_MATRIX.md — stakeholder priorities

If required artifacts do not exist, output an error instructing the user to run previous pipeline phases first, and stop.

Target Architecture Design Process

Design the target architecture by:

Preserve What Works

1. Identify components from the as-is model that are well-architected
2. Mark components that should be preserved as-is
3. Mark components that need minor adjustments vs major redesign

Address Gaps Systematically

4. For each P0 gap: design a direct remediation in the target architecture
5. For each P1 gap: design architectural changes that resolve the gap
6. For P2/P3 gaps: design improvements that can be applied incrementally

Architecture Decision Records

7. For each significant architectural change, create an ADR with:
   • Context: what gap/risk motivates this change
   • Decision: what architectural choice was made
   • Consequences: tradeoffs and implications
   • Status: proposed

Component Architecture

8. Design target component diagram showing:
   • Retained components (unchanged)
   • Modified components (with change annotations)
   • New components (added to address gaps)
   • Removed components (with justification)

Technology Recommendations

9. Recommend technology changes where gaps demand them
10. Justify each technology change with evidence from gap analysis
11. Prefer minimal technology changes that address maximum gaps

Skill Loading

Load the target architecture skill:

Read ${CLAUDE_PLUGIN_ROOT}/skills/target-architecture/SKILL.md

Follow the skill instructions to generate the target architecture document.

Output

Write to the output directory:

1. TO_BE_ARCHITECTURE.md — Target architecture document containing:
   • Architecture vision and principles
   • Target component diagram (Mermaid)
   • Change delta from as-is (what changes, what stays)
   • Architecture Decision Records (ADRs)
   • Technology stack recommendations
   • Non-functional requirements addressed
   • Traceability to gap IDs (GAP-NNNN)