# SDD + GitOps Documentation Framework ## Overview The **SDD + GitOps Documentation Framework** is a comprehensive, structured approach to software development documentation that aligns technical work with business outcomes through clear separation of concerns. This framework ensures that every piece of documentation serves a specific purpose, reaches the right audience, and can be measured for effectiveness. It's designed to prevent common pitfalls like feature creep, communication gaps, and operational fragility. --- ## The Documentation Matrix | Document | Purpose & Rationale (The "Why") | Audience | Format / Content | Measurement (KPI/SLO) | Example (SaaS Context) | |----------|----------------------------------|----------|------------------|----------------------|------------------------| | **Requirements** | The Business North Star. Defines exactly what problem the user has and what success looks like. It prevents "feature creep" by setting hard boundaries on what we will NOT build. | Founder, Team, PM | Format: Shared Wiki (Notion/GitHub Wiki). Content: User stories, business constraints, competitive context, and success metrics. | **KPI**: Business Outcomes. Measured by User Retention, Conversion Rates, and Monthly Recurring Revenue (MRR). | "The system must process high-volume math so clients see reports instantly. Goal: 15% increase in daily active users." | | **Spec** | The Technical Contract. A machine-readable, strictly typed definition of all data interfaces. It is the "Single Source of Truth" that prevents bugs caused by communication gaps between services. | Developers, QA, Automation | Format: OpenAPI/YAML or Protobuf. Content: API endpoints, snake_case key naming, data validation rules, and error response codes. | **SLA/SLO**: System Performance. Measured by API Uptime (99.9%), Response Latency (<100ms), and Error Rates. | A `contract.yaml` defining exactly how Julia sends Arrow data to Node.js. It forces `user_id` to be a UUID. | | **Architecture** | The Structural Blueprint. A visual map of how the components (services, DBs, networks) fit together. It shows how the data flows through the 6-node cluster and where bottlenecks live. | Senior Devs, DevOps | Format: Diagrams-as-code (Mermaid.js). Content: System Context diagrams, Database ERDs, Network Security Policies, and Infrastructure maps. | **Efficiency Metrics**: Resource utilization. Measured by CPU Load (<70%), RAM per pod, and internal network throughput. | A diagram showing the data path: Caddy (Proxy) → Node.js (API) → NATS (Queue) → Julia (Math Engine). | | **Walkthrough** | The Intuition & Logic. A narrative guide that explains the "steps" and "rationale" behind end-to-end flows. It's about building a mental model so devs understand why the sequence matters. | The Team, New Hires | Format: TOUR.md file or Loom Video. Content: Step-by-step traces of core features, explanation of architectural trade-offs, and "The Big Picture" flow. | **Quality**: Developer Velocity. Measured by "Time-to-First-Commit" for new hires and reduction in conceptual bugs. | "End-to-End Trace": 1. UI sends JSON. 2. API wraps it in Claim-Check. 3. Julia pulls it. Rationale: To avoid NATS memory spikes. | | **Implementation** | The Functional Reality. The actual code that does the work. In SDD, the "boring" parts (types/routes) are auto-generated from the Spec to ensure the code never lies. | Developers, Reviewers | Format: Git Repository. Content: Business logic, internal helper functions, Unit Tests, and a README.md for local environment setup. | **Code Health**: Internal Quality. Measured by Test Coverage (90%+), Linting compliance, and Cyclomatic Complexity. | The SvelteKit frontend components and the specific Julia math-processing functions. | | **Validation** | The Enforcement Layer. Automated gates that prove the Implementation matches the Spec. It prevents human error (like changing a key name) from reaching production. | CI/CD Pipeline, QA | Format: GitHub Actions / Tests. Content: Contract tests (Dredd/Prism), Integration tests, and Security scans that run on every pull request. | **Compliance**: Safety Metrics. Measured by Build Success Rate and 0 "Contract Violations" in the production logs. | A CI job that blocks a Pull Request because a developer used camelCase in a database field instead of snake_case. | | **Maintenance** | The Health & Evolution. Defines how to upgrade dependencies, manage technical debt, and rotate secrets. It's the guide for "future-proofing" the software over time. | The Team, DevOps | Format: MAINTENANCE.md. Content: Dependency update schedules, Secret rotation steps, DB Migration logs, and Tech Debt "Graveyard" tracking. | **Sustainability**: System Longevity. Measured by "Package Age", "Security Vulnerabilities Found", and "Migration Success Rate". | "Steps to upgrade the Julia version across all 6 nodes without downtime using a Blue-Green deployment strategy." | | **Runbook** | The Operational Life-Support. The instructions for when the system is alive (or dying). In GitOps, this is the "Desired State" of the infrastructure. | DevOps, SRE, On-call Devs | Format: K8s Manifests (Flux/Argo). Content: Deployment steps, Scaling triggers, Backup/Restore procedures, and "3:00 AM" troubleshooting guides. | **Reliability**: Operational Health. Measured by MTTR (Mean Time to Recovery) and Error-Free Deployments. | A Flux manifest that ensures 6 replicas of the Julia service are always healthy and restarts them if they hit 80% RAM. | --- ## Detailed Document Descriptions ### 1. Requirements **Purpose**: Establish the Business North Star. **Why It Matters**: Without clear requirements, teams drift into "feature creep" - building things that don't solve the actual problem. This document anchors the project in business outcomes. **Key Elements**: - **User Stories**: What the user needs to accomplish - **Business Constraints**: Budget, timeline, regulatory requirements - **Competitive Context**: What competitors do and how you differentiate - **Success Metrics**: Quantifiable goals that define "done" **Best Practices**: - Keep it in a shared wiki (Notion, GitHub Wiki) for collaborative editing - Focus on outcomes, not solutions - Explicitly state what you will NOT build --- ### 2. Spec (Specification) **Purpose**: Create a machine-readable technical contract. **Why It Matters**: Communication gaps between services cause bugs. A strict, typed spec prevents these by being the Single Source of Truth. **Key Elements**: - **API Endpoints**: All routes with HTTP methods - **Data Types**: Strict typing with validation rules - **Error Codes**: Comprehensive error response definitions - **Naming Conventions**: snake_case keys, consistent patterns **Best Practices**: - Use OpenAPI (YAML/JSON) for REST APIs or Protobuf for gRPC - Automate generation of client/server code from the spec - Run contract tests against the spec in CI/CD --- ### 3. Architecture **Purpose**: Visualize the system structure and data flow. **Why It Matters**: Complex systems (like your 6-node cluster) need clear maps. Without them, teams can't identify bottlenecks or make informed decisions. **Key Elements**: - **System Context Diagram**: Shows the system and its external dependencies - **Database ERD**: Entity-Relationship diagrams for data model - **Network Security Policies**: Firewall rules, service mesh configs - **Infrastructure Maps**: Cloud resources, scaling groups **Best Practices**: - Use Mermaid.js for diagrams-as-code (versionable, diffable) - Update diagrams when architecture changes - Focus on data flow and decision points --- ### 4. Walkthrough **Purpose**: Build a mental model through narrative. **Why It Matters**: Code doesn't explain *why*. Walkthroughs capture the reasoning behind architectural trade-offs, making onboarding faster and reducing conceptual bugs. **Key Elements**: - **Step-by-step traces**: End-to-end flow of user actions - **Trade-off explanations**: Why you chose option A over B - **The Big Picture**: How components fit together conceptually **Best Practices**: - Write in a TOUR.md file or record Loom videos - Focus on intuition, not just mechanics - Include "Rationale" sections for each major decision --- ### 5. Implementation **Purpose**: The functional reality - the actual code. **Why It Matters**: This is what runs in production. In SDD, the spec-driven approach ensures boring parts are generated automatically, so developers focus on business logic. **Key Elements**: - **Business Logic**: The unique value you provide - **Unit Tests**: Covering edge cases and error paths - **README.md**: Local environment setup instructions **Best Practices**: - Generate boilerplate (types, routes) from the Spec - Maintain 90%+ test coverage - Keep README.md up-to-date for local development --- ### 6. Validation **Purpose**: Automated quality gates. **Why It Matters**: Human error happens. Validation layers catch mistakes before they reach production, preventing contract violations and security issues. **Key Elements**: - **Contract Tests**: Verify implementation matches spec (Dredd, Prism) - **Integration Tests**: Test service-to-service interactions - **Security Scans**: SAST/SBOM analysis on every PR **Best Practices**: - Run validation on every pull request - Block merges on contract violations - Track build success rate as a KPI --- ### 7. Maintenance **Purpose**: Guide for long-term health and evolution. **Why It Matters**: Software decays. Without a maintenance plan, dependency upgrades become risky, secrets accumulate, and technical debt piles up. **Key Elements**: - **Dependency Update Schedule**: When and how to upgrade packages - **Secret Rotation Steps**: How to rotate credentials securely - **DB Migration Logs**: History of schema changes - **Tech Debt "Graveyard"**: Documented technical debt with remediation plans **Best Practices**: - Document the "how" for common maintenance tasks - Track package age and security vulnerabilities - Schedule regular tech debt reviews --- ### 8. Runbook **Purpose**: Operational life-support for production systems. **Why It Matters**: When production is down, teams need clear instructions. In GitOps, the runbook is the "desired state" that the system constantly works toward. **Key Elements**: - **Deployment Steps**: How to deploy new versions - **Scaling Triggers**: When and how to scale up/down - **Backup/Restore Procedures**: Disaster recovery steps - **"3:00 AM" Troubleshooting**: Quick fixes for common failures **Best Practices**: - Store in K8s manifests (Flux/Argo) for GitOps - Automate as much as possible - Test runbook procedures regularly --- ## How to Use This Framework 1. **Start with Requirements** - Define the business problem and success criteria 2. **Create the Spec** - Translate requirements into machine-readable contracts 3. **Design Architecture** - Visualize how the system will work 4. **Write Walkthrough** - Document the logic and trade-offs 5. **Implement** - Build the actual code 6. **Set up Validation** - Add automated tests and gates 7. **Document Maintenance** - Plan for long-term health 8. **Create Runbook** - Define operational procedures This framework ensures that every document serves a clear purpose and that your project remains maintainable, scalable, and aligned with business goals.