Getting Started with Spec-Driven Development
Overview
Adopting spec-driven development doesn't require a complete workflow overhaul. Start small, learn the fundamentals, and gradually increase adoption as you see benefits.
Step 1: Understand Context Engineering
Before diving into tools, understand the foundational concept:
- Learn context engineering - The practice of structuring information for AI agents
- Recognize the problem: Vibe coding leads to drift between intent and implementation
- Understand the solution: Explicit specifications provide clear reference points
Step 2: Choose Your Starting Point
Option A: Start Tactical (Recommended for Beginners)
Begin with plan mode in your existing AI assistant:
- For your next feature, ask the AI to create a plan first
- Review and refine the plan before implementation
- Notice how explicit planning reduces iteration cycles
Option B: Start Strategic
Choose a dedicated SDD tool and try it on a small feature:
- OpenSpec: Good for unified specifications and brownfield projects
- GitHub Spec Kit: Natural fit if you're already on GitHub
- Kiro: Easiest learning curve with all-in-one IDE
Step 3: Write Your First Spec
Start simple. A good first spec includes:
- What it does: Clear description of the feature
- Requirements: Explicit list of what must be true
- Scenarios: Concrete examples of expected behavior
- Constraints: What the feature should NOT do
Example: Simple Login Spec
## Login Feature
**What it does:** Allows registered users to access the application.
**Requirements:**
- SHALL accept email and password
- SHALL validate email format before submission
- SHALL display error for invalid credentials
- SHALL redirect to dashboard on successful login
- SHALL rate-limit to 5 attempts per 15 minutes
**Scenarios:**
1. Valid credentials → redirect to /dashboard
2. Invalid credentials → show error, do not redirect
3. Empty fields → show validation errors
4. 6th failed attempt → show rate limit message
**Constraints:**
- SHALL NOT store passwords in plain text
- SHALL NOT allow brute force attacks
- SHALL NOT expose whether email existsStep 4: Implement and Validate
- Give spec to AI: Use your spec to guide AI implementation
- Validate scenarios: Check that each scenario works as specified
- Iterate on spec: Update spec if you discover requirements were incomplete
- Keep spec synchronized: When implementation changes, update the spec
Step 5: Gradual Adoption
Expand SDD usage based on what works:
- If plan mode works: Continue using it for more features
- If you need more rigor: Graduate to a dedicated SDD tool
- If specs help: Apply to more complex features first
- If validation matters: Focus on critical business logic and security features
Not every feature needs a formal spec. Use SDD where clarity and correctness matter most.
Common Mistakes to Avoid
- Over-specifying: Don't write specs longer than the code. Stay focused on requirements and scenarios.
- Under-specifying: Specs that just repeat the feature name aren't helpful. Include concrete scenarios.
- Spec rot: Keep specs updated when implementation changes, or they become worse than no spec.
- All-or-nothing: You don't need specs for everything. Start with critical features.