When to Use This Skill

/scenario-compare

Compare multiple architectural scenarios with detailed cost, timeline, complexity, risk, and benefit analysis. Uses three parallel agents to evaluate financial, technical, and risk dimensions simultaneously, then produces a weighted decision matrix with a clear recommendation.

When to Use This Skill

• Choosing between 2-4 architectural approaches for a problem
• Comparing build vs buy vs integrate options
• Evaluating technology platform alternatives
• Preparing options papers for architecture governance boards
• Making vendor or product selection decisions

Usage

/scenario-compare <scenario-1> vs <scenario-2> [vs <scenario-3>] [--criteria cost,risk,time,complexity]

Parameters

Instructions

Phase 1: Define Scenarios

For each scenario, gather:

Also gather evaluation context:

• Decision deadline — When must the decision be made?
• Budget constraints — Any hard budget limits?
• Non-negotiables — Must-have requirements that eliminate options?

Phase 2: Parallel Scenario Analysis — Agent Team

Launch three agents simultaneously using the Task tool. Each agent evaluates all scenarios across one dimension.

Agent 1: Cost and Financial Analyst (Sonnet) Task: Compare financial implications of each scenario

• Calculate setup/implementation costs per scenario
• Calculate annual operating costs per scenario (infrastructure, licensing, staffing)
• Compute 3-year and 5-year Total Cost of Ownership (TCO)
• Calculate Return on Investment (ROI) and payback period
• Run sensitivity analysis (best case, expected, worst case — ±20% variance)
• Identify hidden costs (migration, training, opportunity cost, technical debt) Return: Financial comparison matrix with TCO, ROI, and sensitivity ranges

Agent 2: Technical and Complexity Analyst (Sonnet) Task: Compare technical characteristics of each scenario

• Score technology stack maturity and ecosystem (0-10)
• Score operational complexity (deployment, monitoring, debugging) (0-10)
• Score vendor dependency and lock-in risk (0-10)
• Assess data migration complexity and approach
• Evaluate scalability potential (vertical, horizontal, elasticity)
• Assess integration effort with existing systems
• Score team skill alignment (current skills vs required skills) (0-10) Return: Technical comparison with radar chart data (5+ dimensions per scenario)

Agent 3: Risk and Timeline Analyst (Sonnet) Task: Compare risks and delivery timelines

• Estimate implementation timeline per scenario (optimistic, expected, pessimistic)
• Identify critical path and key dependencies per scenario
• Score risks per scenario across categories (technical, organisational, financial, schedule)
• Create risk probability x impact matrix per scenario
• Identify go/no-go criteria and decision gates
• Assess reversibility — how hard is it to change course after committing? Return: Timeline comparison and risk assessment data per scenario

Phase 3: Synthesise Comparison

Combine all agent results:

1. Build weighted decision matrix — Score each scenario against all criteria
2. Create side-by-side comparison — Visual summary of key differences
3. Generate recommendation — Clear recommendation with reasoning
4. Document trade-offs — What you gain and lose with each option
5. Define decision criteria — Go/no-go checklist for the recommended option

Default Weights:

Output Format

# Scenario Comparison: <Context>

## Executive Summary

**Recommended:** Scenario X — <Name>
**Confidence:** High/Medium/Low

<2-3 sentence justification>

## Scenarios at a Glance

| Dimension         | Scenario A        | Scenario B        | Scenario C        |
|-------------------|-------------------|-------------------|-------------------|
| Approach          | <summary>         | <summary>         | <summary>         |
| Timeline          | X months          | X months          | X months          |
| 3-Year TCO        | £Xk               | £Xk               | £Xk               |
| Risk Level        | Low/Med/High      | Low/Med/High      | Low/Med/High      |
| Complexity        | X/10              | X/10              | X/10              |

## Cost Comparison

| Cost Category       | Scenario A  | Scenario B  | Scenario C  |
|---------------------|-------------|-------------|-------------|
| Setup costs         | £X          | £X          | £X          |
| Annual operating    | £X          | £X          | £X          |
| 3-Year TCO          | £X          | £X          | £X          |
| 5-Year TCO          | £X          | £X          | £X          |
| ROI (3-year)        | X%          | X%          | X%          |
| Payback period      | X months    | X months    | X months    |

### Sensitivity Analysis

| Scenario   | Best Case TCO | Expected TCO | Worst Case TCO |
|------------|---------------|--------------|----------------|
| A          | £X            | £X           | £X             |

## Technical Comparison

### Complexity Radar

| Dimension             | Scenario A | Scenario B | Scenario C |
|-----------------------|------------|------------|------------|
| Stack maturity        | X/10       | X/10       | X/10       |
| Operational complexity| X/10       | X/10       | X/10       |
| Vendor lock-in        | X/10       | X/10       | X/10       |
| Skill alignment       | X/10       | X/10       | X/10       |
| Scalability           | X/10       | X/10       | X/10       |

## Risk Comparison

| Risk Category    | Scenario A       | Scenario B       | Scenario C       |
|------------------|------------------|------------------|------------------|
| Technical        | <score + detail> | <score + detail> | <score + detail> |
| Organisational   | <score + detail> | <score + detail> | <score + detail> |
| Financial        | <score + detail> | <score + detail> | <score + detail> |
| Schedule         | <score + detail> | <score + detail> | <score + detail> |

## Timeline Comparison

| Milestone          | Scenario A  | Scenario B  | Scenario C  |
|--------------------|-------------|-------------|-------------|
| Planning complete  | Month X     | Month X     | Month X     |
| MVP / Phase 1      | Month X     | Month X     | Month X     |
| Full delivery      | Month X     | Month X     | Month X     |
| Benefits realised  | Month X     | Month X     | Month X     |

## Weighted Decision Matrix

| Criterion (Weight)       | Scenario A | Scenario B | Scenario C |
|--------------------------|------------|------------|------------|
| Cost — 25%               | X/10       | X/10       | X/10       |
| Technical fit — 25%      | X/10       | X/10       | X/10       |
| Risk — 20%               | X/10       | X/10       | X/10       |
| Timeline — 15%           | X/10       | X/10       | X/10       |
| Scalability — 15%        | X/10       | X/10       | X/10       |
| **Weighted Total**       | **X.X**    | **X.X**    | **X.X**    |

## Recommendation

**Go with: Scenario X — <Name>**

### Why This Scenario
<Clear reasoning>

### Key Trade-offs Accepted
- <What you give up>

### Go/No-Go Criteria
- [ ] <Criteria that must be true to proceed>

Examples

Example 1: Platform Choice

/scenario-compare Cloud-native rebuild vs Lift-and-shift vs Hybrid migration

Example 2: Integration Approach

/scenario-compare REST API vs Event-driven vs Batch ETL --weights cost=30,risk=30,time=20,complexity=20

Example 3: Build vs Buy

/scenario-compare Custom build vs Commercial platform vs Open-source solution --criteria cost,risk,time

Invoke with: /scenario-compare <scenario-1> vs <scenario-2> [vs <scenario-3>]