claude-plugins/plugins/code-modernization/commands/modernize-brief.md

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description: Generate a phased Modernization Brief — the approved plan that transformation agents will execute against

argument-hint: [target-stack]

Synthesize everything in analysis/$1/ into a Modernization Brief — the single document a steering committee approves and engineering executes.

Target stack: $2 (if blank, recommend one based on the assessment findings).

Read analysis/$1/ASSESSMENT.md, TOPOLOGY.md, and BUSINESS_RULES.md first. If any are missing, say so and stop.

The Brief

Write analysis/$1/MODERNIZATION_BRIEF.md:

1. Objective

One paragraph: from what, to what, why now.

2. Target Architecture

Mermaid C4 Container diagram of the end state. Name every service, data store, and integration. Below it, a table mapping legacy component → target component(s).

3. Phased Sequence

Break the work into 3-6 phases using strangler-fig ordering — lowest-risk, fewest-dependencies first. For each phase:

• Scope (which legacy modules, which target services)
• Entry criteria (what must be true to start)
• Exit criteria (what tests/metrics prove it's done)
• Estimated effort (person-weeks, derived from COCOMO + complexity data)
• Risk level + top 2 risks + mitigation

Render the phases as a Mermaid gantt chart.

4. Behavior Contract

List the P0 behaviors from BUSINESS_RULES.md that MUST be proven equivalent before any phase ships. These become the regression suite.

5. Validation Strategy

State which combination applies: characterization tests, contract tests, parallel-run / dual-execution diff, property-based tests, manual UAT. Justify per phase.

6. Open Questions

Anything requiring human/SME decision before Phase 1 starts. Each as a checkbox the approver must tick.

7. Approval Block

Approved by: ________________  Date: __________
Approval covers: Phase 1 only | Full plan

Present

Enter plan mode and present a summary of the brief. Do NOT proceed to any transformation until the user explicitly approves. This gate is the human-in-the-loop control point.