SDD + TDD Integrated Workflow

Overview

This skill guides AI agents through a comprehensive Specification-Driven Development (SDD) and Test-Driven Development (TDD) integrated workflow: Spec → Test → Code (STC).

The workflow ensures:

• Clear specifications before implementation (RFC/ADR)
• Test cases derived from specifications
• Test-first development (Red-Green-Refactor)
• Validation against specifications
• Iterative refinement

When to Use This Skill

Apply this workflow based on task complexity:

Task Type	Apply Workflow
Complex new features	✅ Full SDD+TDD
Simple new features	⚠️ TDD only (skip RFC)
Technical decisions	✅ ADR + TDD
Bug fixes	⚠️ TDD only
Large-scale refactoring	✅ RFC + TDD
Small-scale refactoring	⚠️ TDD only

Use this skill when:

• User explicitly requests SDD/TDD workflow
• Implementing features that affect multiple components
• Making architectural or technology stack decisions
• Refactoring requires specification documentation
• Working on ai-cli-syncer project or similar spec-driven projects

Core Workflow: 6 Phases

Spec → Design Review → Test → Code → Verify → Iterate

Phase 1: Specification (Spec)

Goal: Define what to build and why.

Choose document type:

• RFC (Request for Comments): New features, user-facing changes, complex refactoring
• ADR (Architecture Decision Record): Technology choices, architectural patterns, data formats

Key sections to complete:

• RFC: Summary, Motivation, Technical Design, Test Strategy
• ADR: Context, Considered Options, Decision Outcome, Consequences

Location: docs/specs/rfcs/ or docs/specs/adrs/

Phase 2: Design Review & Breakdown

Goal: Analyze spec and create implementation plan.

Key Activities:

1. Requirements Breakdown: Decompose spec into implementable units
2. Technical Feasibility: Evaluate technical viability
3. Implementation Planning: Define order, priorities, resources
4. Risk Identification: Identify potential issues and mitigation

Outputs:

• Decomposed requirements list
• Technical feasibility assessment
• Implementation plan (order, timeline, resources)
• Risk matrix with mitigation strategies

Phase 3: Test Definition

Goal: Derive test cases from specifications to define success criteria.

Steps:

1. Extract Acceptance Criteria from spec's Test Strategy section
2. Write test case descriptions (unit + integration)
3. Document test scenarios (happy path, error handling, edge cases)

Format: Given-When-Then structure

Phase 4: TDD Implementation

Goal: Implement using Red-Green-Refactor cycle.

TDD Cycle:

1. Red: Write failing test
2. Green: Write minimal code to pass
3. Refactor: Improve code while keeping tests passing

Repeat for each function/feature.

Phase 5: Verification

Goal: Ensure implementation meets spec and quality standards.

Checklist:

• All tests pass
• Test coverage ≥ 80%
• Spec requirements fulfilled
• Code review completed
• Manual testing successful

Phase 6: Iteration

Goal: Incorporate feedback and update specs as needed.

Steps:

1. Collect feedback (reviews, tests, users)
2. Update spec if implementation discoveries warrant it
3. Update tests to match spec changes
4. Re-verify (return to Phase 5)

Working with AI Agents

Requesting SDD+TDD Workflow

Example prompts:

"Implement the sync command using SDD+TDD workflow from RFC-0001"

"Create an ADR for choosing the configuration format, then implement with TDD"

"Follow SDD+TDD workflow to add user authentication feature"

What the AI Agent Will Do

1. Read and understand the RFC/ADR specification
2. Analyze and break down requirements
3. Create implementation plan and identify risks
4. Derive test cases from Test Strategy section
5. Write tests first (Red)
6. Implement minimal code (Green)
7. Refactor for quality
8. Verify against spec requirements
9. Update spec if needed

Collaboration Tips

• Be explicit: Reference specific RFC/ADR numbers
• Provide context: Share relevant spec sections
• Review checkpoints: Ask agent to verify spec compliance
• Iterate openly: Discuss spec updates during implementation

Resources

references/

full_workflow.md - Comprehensive workflow documentation including:

• Detailed phase-by-phase instructions
• Workflow diagrams
• Practical implementation examples
• Checklists for each phase
• AI agent collaboration patterns

When to load: When detailed guidance is needed for a specific phase, when implementing a complex feature for the first time, or when teaching the workflow to new team members.

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Quick Reference:

Need	Action
Start new feature	RFC → Design Review → Tests → TDD implement
Make tech decision	ADR → Design Review → Tests → TDD implement
Understand phases	Read references/full_workflow.md
Get examples	See "실전 예제" section in full_workflow.md
Use checklist	Find phase checklists in full_workflow.md