System Analysis (SA) Skill

This skill focuses on System Analysis & Design, aiming to transform business requirements from the PRD into executable technical solutions. SA is the bridge connecting "What to do" (PRD) with "How to do" (Code).

SA Core Responsibilities

1. Architecture Design: Define the high-level system structure, module divisions, and responsibilities.
2. Data Modeling: Design database schema, data structures, and storage strategies.
3. Interface Design: Define API specifications, function signatures, and interaction protocols.
4. Process Logic: Clarify complex business logic through diagrams (Flowchart, Sequence Diagram).
5. Testing Strategy: [Critical] Analyze the impact of changes on existing tests and define the testing plan.

SA Artifacts

• System Design Document (SDD): The system design specification. See references/system_design_doc.md.
• API Specification: API specification document (Swagger/OpenAPI or Markdown).
• Database Schema: ER Model or JSON Schema definitions.

How to Use This Skill

When a user needs technical evaluation or design (e.g., "Help me plan the data structure for this feature"):

1. Analyze: Review the PRD and confirm technical feasibility of all functional requirements.
2. Model:
   • Data: Design JSON objects or DB Tables.
   • Process: Draw Mermaid Sequence Diagrams.
3. Validate Tests:
   • Search for all test files related to the changed modules (grep/find).
   • Analyze whether test code depends on internal implementations or DOM structures being changed.
   • Explicitly list test files that must be modified and DOM structures that must be preserved in the SA document.
4. Design: Fill out the system_design_doc.md template.
5. Review: Have the user confirm the technical solution complies with project architecture standards.

Common Tools

• Mermaid: For drawing flowcharts, sequence diagrams, class diagrams, and state diagrams. See references/diagram_guide.md.
• TypeScript / JSDoc: For precisely defining data types and interfaces.

Checklist

• Have edge cases been considered?
• Is the data structure extensible?
• Does it comply with existing code style and architecture patterns?
• Has performance impact been evaluated?
• [Must] Have all affected test cases been identified, and is there a plan to update tests in sync with code changes?