| name | arckit-sobc |
| description | Create Strategic Outline Business Case (SOBC) using UK Government Green Book 5-case model |
You are helping an enterprise architect create a Strategic Outline Business Case (SOBC) to justify investment in a technology project.
About SOBC
A Strategic Outline Business Case (SOBC) is the first stage in the UK Government business case lifecycle:
- SOBC: Strategic Outline (this command) - High-level case for change, done BEFORE detailed requirements
- OBC: Outline Business Case - After some design work, with refined costs
- FBC: Full Business Case - Detailed case with accurate costs, ready for final approval
This command creates the SOBC - the strategic case to secure approval to proceed with requirements and design.
User Input
$ARGUMENTS
Instructions
Note: Before generating, scan projects/ for existing project directories. For each project, list all ARC-*.md artifacts, check external/ for reference documents, and check 000-global/ for cross-project policies. If no external docs exist but they would improve output, ask the user.
This command creates a Strategic Outline Business Case (SOBC) following HM Treasury Green Book 5-case model. This is a high-level justification done BEFORE detailed requirements to secure approval and funding.
When to use this:
- After:
$arckit-stakeholders (MANDATORY - SOBC must link to stakeholder goals)
- Before:
$arckit-requirements (SOBC justifies whether to proceed with detailed requirements)
- Purpose: Secure executive approval and funding to proceed to next stage
Note: Later stages will create OBC (Outline Business Case) and FBC (Full Business Case) with more accurate costs. This SOBC uses strategic estimates and options analysis.
-
Read existing artifacts from the project context:
MANDATORY (warn if missing):
- STKE (Stakeholder Analysis) in
projects/{project}/
- Extract: ALL stakeholder goals (become benefits), drivers (explain WHY needed), conflicts (become risks/mitigations), outcomes (become success criteria)
- If missing: STOP and warn user to run
$arckit-stakeholders first — every SOBC benefit MUST trace to a stakeholder goal
RECOMMENDED (read if available, note if missing):
- PRIN (Architecture Principles, in
projects/000-global/)
- Extract: Strategic alignment, technology standards, compliance requirements
- RISK (Risk Register) in
projects/{project}/
- Extract: Risks for Management Case, risk appetite, mitigations
OPTIONAL (read if available, skip silently if missing):
- REQ (Requirements) in
projects/{project}/
- Extract: Detailed requirements for more accurate cost estimates
- PLAN (Project Plan) in
projects/{project}/
- Extract: Timeline, phasing for Commercial Case delivery schedule
- TNDR (Procurement Market Intelligence) at
projects/{project}/research/ARC-{P}-TNDR-*.md
- If found: extract the median award value and award count as a market-context benchmark for the Economic Case options analysis — e.g. to sanity-check an option's Rough Order of Magnitude cost against what comparable work has been awarded for in the market
- Critical: awarded value is NOT actual spend and must NOT be used as the costed figure; cite it as market context and market view only, with that caveat stated explicitly whenever the figure appears
- If no TNDR artefact exists, skip silently
-
Understand the request: The user may be:
- Creating initial SOBC (most common)
- Updating existing SOBC with new information
- Creating UK Government Green Book 5-case model (automatic for UK projects)
- Evaluating multiple strategic options
-
Read external documents and policies:
- Read any external documents listed in the project context (
external/ files) — extract budget allocations, cost forecasts, financial constraints, existing spend data, benefit projections
- Read any global policies listed in the project context (
000-global/policies/) — extract spending thresholds, approval gates, Green Book discount rates, procurement rules
- Read any enterprise standards in
projects/000-global/external/ — extract enterprise investment frameworks, strategic business plans, cross-project portfolio investment context
- If no external docs exist but they would improve the business case, ask: "Do you have any budget documents, financial forecasts, or market research? I can read PDFs directly. Place them in
projects/{project-dir}/external/ and re-run, or skip."
- Citation traceability: When referencing content from external documents, follow the citation instructions in
.arckit/references/citation-instructions.md. Place inline citation markers (e.g., [PP-C1]) next to findings informed by source documents and populate the "External References" section in the template.
-
Determine project context:
- If user mentions "UK Government", "public sector", "department", "ministry" → Use full Green Book format
- Otherwise → Use Green Book structure but adapt language for private sector
- Check stakeholder analysis for government-specific stakeholders (Minister, Permanent Secretary, Treasury, NAO)
-
Read stakeholder analysis carefully:
- Extract ALL stakeholder goals (these become benefits!)
- Extract stakeholder drivers (these explain WHY project needed)
- Extract conflicts (these become risks/mitigations)
- Extract outcomes (these become success criteria)
- Note: EVERY benefit in SOBC MUST trace to a stakeholder goal
-
Interactive Configuration:
Before generating the SOBC, ask the user for appraisal preferences. Skip any question the user has already answered in their arguments.
Gathering rules (apply to all questions in this section):
- Ask the most important question first; fill in secondary details from context or reasonable defaults.
- Maximum 2 rounds of questions. After that, pick the best option from available context.
- If still ambiguous after 2 rounds, choose the (Recommended) option and note: "I went with [X] — easy to adjust if you prefer [Y]."
Question 1 — header: Options, multiSelect: false
"How many strategic options should be evaluated in the Economic Case?"
- 4 options (Recommended): Do Nothing + Minimal + Balanced + Comprehensive — standard Green Book options appraisal
- 3 options: Do Nothing + two alternatives — suitable for straightforward investment decisions
- 5 options: Do Nothing + four alternatives — for complex programmes with multiple viable approaches
Question 2 — header: Appraisal, multiSelect: false
"What level of economic appraisal should be applied?"
- Strategic estimates (Recommended): Rough Order of Magnitude costs and qualitative benefits — appropriate for SOBC stage
- Semi-quantitative: ROM costs with quantified key benefits and basic NPV — when some financial data is available
- Full quantitative: Detailed costs, quantified benefits, NPV, BCR, sensitivity analysis — typically for OBC/FBC stage, but may be required for large investments
Apply the user's selections: the option count determines how many alternatives are analyzed in Part B (Economic Case). The appraisal depth determines the level of financial detail, whether NPV/BCR calculations are included, and whether sensitivity analysis is performed.
-
Generate comprehensive SOBC:
Read the template (with user override support):
- First, check if
.arckit/templates-custom/sobc-template.md exists in the project root
- If found: Read the user's customized template (user override takes precedence)
- If not found: Read
.arckit/templates/sobc-template.md (default)
Tip: Users can customize templates with $arckit-customize sobc
Five Cases (HM Treasury Green Book Model):
A. Strategic Case:
- Problem Statement: What's broken? (from stakeholder pain points)
- Strategic Fit: How does this align with organizational strategy?
- Stakeholder Drivers: Map to stakeholder analysis
- Link EACH driver to strategic imperative
- Show intensity (CRITICAL/HIGH/MEDIUM)
- Scope: What's in/out of scope (high-level)
- Dependencies: What else must happen?
- Why Now?: Urgency and opportunity cost
B. Economic Case:
- Options Analysis (CRITICAL):
- Option 0: Do Nothing (baseline)
- Option 1: Minimal viable solution
- Option 2: Balanced approach (often recommended)
- Option 3: Comprehensive solution
- For EACH option:
- High-level costs (rough order of magnitude)
- Benefits delivered (% of stakeholder goals met)
- Risks
- Pros/cons
- Benefits Mapping:
- Link EACH benefit to specific stakeholder goal from ARC-{PROJECT_ID}-STKE-v*.md
- Quantify where possible (use stakeholder outcomes for metrics)
- Categorize: FINANCIAL | OPERATIONAL | STRATEGIC | COMPLIANCE | RISK
- Cost Estimates (high-level):
- Capital costs (build)
- Operational costs (run)
- 3-year TCO estimate
- Economic Appraisal:
- Qualitative assessment (this is strategic, not detailed)
- Expected ROI range
- Payback period estimate
- Recommended Option: Which option and why
C. Commercial Case:
- Procurement Strategy:
- UK Government: Digital Marketplace route (G-Cloud, DOS, Crown Hosting)
- Private Sector: Build vs Buy vs Partner
- Market Assessment:
- Supplier availability
- SME opportunities (UK Gov requirement)
- Competition considerations
- Sourcing Route: How will we acquire this?
- Contract Approach: Framework, bespoke, managed service?
D. Financial Case:
- Budget Requirement: How much needed?
- Funding Source: Where does money come from?
- Approval Thresholds: Who must approve?
- UK Gov: HMT approval needed above £X?
- Private: Board approval needed?
- Affordability: Can organization afford this?
- Cash Flow: When do we need money?
- Budget Constraints: Any spending controls?
E. Management Case:
- Governance:
- Who owns this? (from stakeholder RACI matrix)
- Steering committee membership
- Decision authorities
- Project Approach: Agile? Waterfall? Phased?
- Key Milestones:
- Approval gates
- Major deliverables
- Go-live target
- Resource Requirements:
- Team size (estimate)
- Skills needed
- External support
- Change Management:
- Stakeholder engagement plan (from stakeholder analysis)
- Training needs
- Resistance mitigation (from stakeholder conflict analysis)
- Benefits Realization:
- How will we measure success? (use stakeholder outcomes)
- Who monitors benefits?
- When do we expect to see benefits?
- Risk Management:
- Top 5-10 strategic risks
- Mitigation strategies
- Risk owners (from stakeholder RACI)
-
Ensure complete traceability:
Every element must link back to stakeholder analysis:
Stakeholder Driver D-1 (CFO: Reduce costs - FINANCIAL, HIGH)
→ Strategic Case: Cost pressure driving change
→ Economic Case: Benefit B-1: £2M annual savings (maps to CFO Goal G-1)
→ Financial Case: 18-month payback acceptable to CFO
→ Management Case: CFO sits on steering committee (RACI: Accountable)
→ Success Criterion: CFO Outcome O-1 measured monthly
-
Include decision framework:
- Recommendation: Which option to proceed with?
- Rationale: Why this option? (reference stakeholder goals met)
- Go/No-Go Criteria: Under what conditions do we proceed?
- Next Steps: If approved, what happens next?
- Typically:
$arckit-requirements to define detailed requirements
- Then:
$arckit-business-case-detailed with accurate costs
CRITICAL - Auto-Populate Document Control Fields:
Before completing the document, populate ALL document control fields in the header:
Step 0: Detect Version
Before generating the document ID, check if a previous version exists:
- Look for existing
ARC-{PROJECT_ID}-SOBC-v*.md files in the project directory
- If no existing file: Use VERSION="1.0"
- If existing file found:
- Read the existing document to understand its scope
- Compare against current inputs and requirements
- Minor increment (e.g., 1.0 → 1.1): Scope unchanged — refreshed estimates, updated stakeholder data, corrected details
- Major increment (e.g., 1.0 → 2.0): Scope materially changed — new options added, fundamentally different recommendations, significant new stakeholder goals
- Use the determined version for document ID, filename, Document Control, and Revision History
- For v1.1+/v2.0+: Add a Revision History entry describing what changed from the previous version
Step 1: Construct Document ID
- Document ID:
ARC-{PROJECT_ID}-SOBC-v{VERSION} (e.g., ARC-001-SOBC-v1.0)
Step 2: Populate Required Fields
Auto-populated fields (populate these automatically):
[PROJECT_ID] → Extract from project path (e.g., "001" from "projects/001-project-name")
[VERSION] → Determined version from Step 0
[DATE] / [YYYY-MM-DD] → Current date in YYYY-MM-DD format
[DOCUMENT_TYPE_NAME] → "Strategic Outline Business Case (SOBC)"
[CLASSIFICATION] → Default to ${user_config.default_classification}; if unavailable, use "OFFICIAL" for UK Gov, "INTERNAL" for private sector
[STATUS] → "DRAFT" for new documents
User-specified fields (must be confirmed with user):
[OWNER] → Who owns this business case? (typically from stakeholder RACI matrix)
[REVIEWED_BY] → Who will review? (mark as "PENDING" if not yet reviewed)
[APPROVED_BY] → Who must approve? (mark as "PENDING" if not yet approved)
- Write the output:
- Create or update
projects/NNN-project-name/ARC-{PROJECT_ID}-SOBC-v${VERSION}.md
- Use project directory structure (create if doesn't exist)
- File name pattern:
ARC-{PROJECT_ID}-SOBC-v{VERSION}.md
- Later stages will be:
ARC-{PROJECT_ID}-OBC-v*.md (Outline Business Case), ARC-{PROJECT_ID}-FBC-v*.md (Full Business Case)
- Use appropriate language:
- UK Government: Use Green Book terminology (intervention, public value, social benefit, spending controls)
- Private Sector: Adapt to commercial language (investment, shareholder value, competitive advantage)
- Always: Link to stakeholder analysis for credibility
- Flag uncertainties:
- Mark estimates as "Rough Order of Magnitude (ROM)"
- Flag where more analysis needed
- Note dependencies on external factors
- Recommend sensitivity analysis for key assumptions
Output Format
Provide:
- Location:
projects/NNN-project-name/ARC-{PROJECT_ID}-SOBC-v1.0.md
- Summary:
- "Created Strategic Outline Business Case (SOBC) for [project name]"
- "Analyzed [X] options against [Y] stakeholder goals"
- "Recommended: Option [X] - [name]"
- "Estimated investment: £[X]M over 3 years"
- "Expected benefits: £[X]M over 3 years from [stakeholder goals]"
- "Payback period: [X] months"
- "Business case lifecycle stage: SOBC (strategic outline)"
- Next steps:
- "Present to [approval body] for go/no-go decision"
- "If approved: Run
$arckit-requirements to define detailed requirements"
- "After requirements: Create OBC (Outline Business Case) with refined costs"
- "After design: Create FBC (Full Business Case) for final approval"
- Traceability note:
- "All [X] benefits traced to stakeholder goals in ARC-{PROJECT_ID}-STKE-v*.md"
- "All [Y] risks linked to stakeholder conflict analysis"
Common Patterns
Pattern 1: Technology Modernization:
- Strategic Case: Legacy systems failing, stakeholder frustration high
- Economic Case: 3-5 options from do-nothing to complete rebuild
- Commercial Case: Cloud migration, Digital Marketplace G-Cloud
- Financial Case: £2-5M over 3 years, CFO approval needed
- Management Case: Phased migration, minimal disruption
Pattern 2: New Digital Service:
- Strategic Case: Citizen/customer demand, competitive pressure
- Economic Case: MVP vs full-featured comparison
- Commercial Case: Build in-house vs platform vendor
- Financial Case: £500K-2M year 1, ongoing £200K/year
- Management Case: Agile delivery, beta to live
Pattern 3: Compliance/Risk Driven:
- Strategic Case: Regulatory requirement, audit findings
- Economic Case: Minimum compliance vs best practice
- Commercial Case: Specialist vendors, certification needed
- Financial Case: Non-negotiable spend, insurance cost reduction
- Management Case: Deadline-driven, stakeholder compliance team owns
UK Government Specific Guidance
Key HM Treasury references: The Green Book provides the 5-case model, the Magenta Book provides evaluation design guidance (theory of change, proportionality, impact evaluation), and the Sourcing Playbook covers should-cost modelling and market assessment. See docs/guides/codes-of-practice.md for the full Rainbow of Books mapping.
For UK Government/public sector projects, ensure:
-
Strategic Case includes:
- Policy alignment (manifesto commitments, departmental objectives)
- Public value (not just efficiency, but citizen outcomes)
- Minister/Permanent Secretary drivers
- Parliamentary accountability
-
Economic Case includes:
- Social Cost Benefit Analysis (if required)
- Green Book discount rates (3.5% standard)
- Optimism bias adjustment (add contingency)
- Wider economic benefits
-
Commercial Case includes:
- Digital Marketplace assessment (G-Cloud, DOS)
- SME participation commitment
- Social value (minimum 10% weighting)
- Open source consideration
-
Financial Case includes:
- HM Treasury approval thresholds
- Spending Review settlement alignment
- Value for money assessment
- Whole-life costs
-
Management Case includes:
- Service Standard assessment plan
- GDS/CDDO engagement
- Cyber security (NCSC consultation)
- Accessibility (WCAG 2.2 AA compliance)
- Data protection (ICO/DPIA requirements)
Error Handling
If stakeholder analysis doesn't exist:
- DO NOT proceed with SOBC
- Tell user: "SOBC requires stakeholder analysis to link benefits to stakeholder goals. Please run
$arckit-stakeholders first."
If user wants detailed business case:
- Tell user: "This command creates SOBC (Strategic Outline Business Case) - the first stage with high-level estimates. After
$arckit-requirements, create OBC (Outline Business Case) with refined costs. After design, create FBC (Full Business Case) for final approval."
If project seems too small for full 5-case:
- Still use 5-case structure but scale appropriately
- Smaller projects: 2-3 pages per case
- Major programmes: 10-20 pages per case
Template Reference
Use the template at .arckit/templates/sobc-template.md as the structure. Fill in with:
- Stakeholder analysis data (goals, drivers, outcomes, conflicts)
- Architecture principles (strategic alignment)
- User's project description
- Industry/sector best practices
- UK Government guidance (if applicable)
Output Instructions
CRITICAL - Token Efficiency:
To avoid exceeding Codex output limits, you MUST use the following strategy:
1. Generate SOBC Document
Create the comprehensive, executive-ready Strategic Outline Business Case following the 5-case model template structure.
Before writing the file, read .arckit/references/quality-checklist.md and verify all Common Checks plus the SOBC per-type checks pass. Fix any failures before proceeding.
2. Write Directly to File
Use the Write tool to create projects/[PROJECT]/ARC-{PROJECT_ID}-SOBC-v${VERSION}.md with the complete SOBC document.
DO NOT output the full document in your response. This would exceed token limits.
3. Show Summary Only
After writing the file, show ONLY a concise summary:
## SOBC Complete ✅
**Project**: [Project Name]
**File Created**: `projects/[PROJECT]/ARC-{PROJECT_ID}-SOBC-v1.0.md`
### SOBC Summary
**Strategic Case**:
- Strategic Alignment: [Brief summary of how project aligns with strategy]
- Spending Objectives: [List 3-5 key objectives linked to stakeholder goals]
- Critical Success Factors: [3-5 CSFs]
**Economic Case**:
- Options Appraised: [Number] options evaluated
- Preferred Option: [Option number and name]
- NPV over [X] years: £[Amount]
- BCR (Benefit-Cost Ratio): [Ratio]
- Key Benefits: [Top 3-5 benefits with £ values]
**Commercial Case**:
- Procurement Route: [e.g., Digital Marketplace, G-Cloud, Open tender]
- Contract Strategy: [e.g., Single supplier, Framework, Multi-supplier]
- Risk Allocation: [Public/Private split]
**Financial Case**:
- Total Budget Required: £[Amount]
- Funding Source: [e.g., Spending Review settlement, reserves]
- Affordability: [Confirmed/To be confirmed]
- Cash Flow: [Summary of phasing]
**Management Case**:
- Project Approach: [Agile/Waterfall/Hybrid]
- Governance: [Board/SRO structure]
- Key Risks: [Top 3-5 risks]
- Timeline: [Start] - [End] ([Duration])
**UK Government Specific** (if applicable):
- Green Book Compliance: [5-case model, options appraisal, sensitivity analysis]
- Technology Code of Practice: [Points addressed]
- Service Standard: [Assessment plan]
- Social Value: [% weighting in procurement]
### What's in the Document
- Executive Summary (2-3 pages)
- Strategic Case: Why we need to act (10-15 pages)
- Economic Case: Options and value for money (15-20 pages)
- Commercial Case: Procurement approach (5-10 pages)
- Financial Case: Funding and affordability (5-10 pages)
- Management Case: Delivery capability (10-15 pages)
- Appendices: Stakeholder analysis, risk register, assumptions
**Total Length**: [X] pages (ready for senior leadership and Treasury approval)
### Next Steps
- Review `ARC-{PROJECT_ID}-SOBC-v1.0.md` for full SOBC document
- Present to Senior Responsible Owner (SRO) for approval
- If approved, run `$arckit-requirements` to define detailed requirements
- After requirements, refine to Outline Business Case (OBC) with firmer costs
Statistics to Include:
- Number of options evaluated
- NPV and BCR for preferred option
- Total budget required
- Timeline (start date - end date)
- Number of stakeholder goals addressed
- Number of critical success factors
- Number of key risks identified
Generate the SOBC now, write to file using Write tool, and show only the summary above.
Important Notes
- Markdown escaping: When writing less-than or greater-than comparisons, always include a space after
< or > (e.g., < 3 seconds, > 99.9% uptime) to prevent markdown renderers from interpreting them as HTML tags or emoji
Suggested Next Steps
After completing this command, consider running:
$arckit-requirements -- Define detailed requirements after SOBC approval
$arckit-roadmap -- Create strategic roadmap from SOBC investment plan
$arckit-tenders -- Anchor the Economic Case market view with real UK award-value benchmarks (when UK government procurement context)