Planning-First Development: How Markdown Documents Drive Structured AI-Assisted Development
Start with a Plan, Not with Code
The most effective development sessions with GenAI agents like Claude Code don't begin with writing code—they begin with writing a plan. A well-structured markdown planning document becomes the North Star for your entire development effort, transforming chaotic AI interactions into purposeful, traceable work.
The Planning Document Pattern
Before typing a single line of code, create a markdown document that outlines:
Project objectives and success criteria
Technical requirements and constraints
Development phases with clear deliverables
Dependencies and integration points
Testing strategy (leveraging TDD principles)
This document becomes the shared context between you and Claude Code throughout the development lifecycle.
How Claude Code Transforms Plans into Structured Work
When you provide Claude Code with a planning document, something remarkable happens: it naturally organizes work into phases with detailed todo lists. A typical response might look like:
## Phase 1: Core Infrastructure
- [ ] Set up project structure
- [ ] Define TypeScript interfaces
- [ ] Create base classes with stub implementations
- [ ] Write initial unit tests
## Phase 2: Feature Implementation
- [ ] Implement user authentication
- [ ] Add data persistence layer
- [ ] Create API endpoints
- [ ] Validate with integration tests
## Phase 3: Polish and Deploy
- [ ] Add error handling
- [ ] Implement logging
- [ ] Create deployment configuration
- [ ] Document API endpoints
From AI-Generated Plans to Work Management Systems
The structured output from Claude Code integrates seamlessly with project management tools:
GitHub Issues
Each phase becomes an issue, with todo items as task lists:
### Issue: Phase 1 - Core Infrastructure
- [ ] Set up project structure
- [ ] Define TypeScript interfaces
- [ ] Create base classes
- [ ] Write unit tests
Jira Stories
Convert phases into epics and todos into stories with clear acceptance criteria derived from your planning document.
Azure DevOps/Linear/Asana
The markdown format translates directly into work items, maintaining traceability from plan to implementation.
The Planning-First Workflow
1. Initial Planning Session
Start with Claude Code to create a comprehensive planning document:
"Help me create a planning document for building a REST API for user management with authentication, role-based access, and audit logging"
2. Review and Refine
Iterate on the plan, adding constraints, technical decisions, and success metrics.
3. Reference During Development
Begin each coding session by referencing the plan:
"Let's implement Phase 1 from our planning document, using TDD methodology"
4. Track Progress
Claude Code will naturally update todo lists as work progresses, providing real-time visibility into completion status.
Combining Planning with TDD
As discussed in my post about taming GenAI agents with TDD, test-driven development provides the tactical discipline for writing code. Planning documents provide the strategic vision. Together, they create a powerful framework:
Planning Document: Defines what to build and why
TDD Approach: Defines how to build it with quality
Your planning document should explicitly reference your TDD strategy:
## Development Methodology
- All features will be developed using Test-Driven Development
- Each component will have unit tests before implementation
- Integration tests will validate phase completion
- Refer to project CLAUDE.md for TDD guidelines
Real-World Example
Here's a planning document excerpt that drives focused development:
# Payment Processing Module Plan
## Objective
Implement secure payment processing with multiple gateway support
## Technical Approach
- TDD methodology for all components
- Hexagonal architecture for gateway abstraction
- Comprehensive error handling and retry logic
## Phase 1: Core Abstractions (Week 1)
### Deliverables
- [ ] Payment interface definitions
- [ ] Gateway adapter pattern implementation
- [ ] Unit tests for all abstractions
- [ ] Mock gateway for testing
## Phase 2: Gateway Integration (Week 2)
### Deliverables
- [ ] Stripe gateway adapter
- [ ] PayPal gateway adapter
- [ ] Integration test suite
- [ ] Error handling scenarios
## Success Criteria
- 100% unit test coverage
- All payment scenarios handled
- Graceful degradation on gateway failure
- Audit trail for all transactions
Benefits of Planning-First Development
1. Coherent Architecture
Starting with a plan ensures architectural decisions are made holistically, not piecemeal.
2. Measurable Progress
Todo lists provide concrete checkpoints, making progress visible and measurable.
3. Reduced Context Switching
The planning document maintains context across sessions, reducing the need to re-explain requirements.
4. Team Collaboration
Planning documents become living specifications that team members can review, comment on, and contribute to.
5. Audit Trail
From plan to code to deployment, you have a complete record of decisions and implementations.
Best Practices
Keep Plans Version Controlled: Store planning documents alongside code in your repository
Update as You Learn: Plans should evolve as implementation reveals new insights
Reference Frequently: Start each Claude Code session by referencing the relevant plan section
Link to Standards: Reference your CLAUDE.md file for coding standards and TDD approach
Export to Work Tracking: Regularly sync plan progress with your project management tools
Conclusion
Planning-first development transforms AI-assisted coding from reactive to proactive. By starting with a structured markdown document, you provide Claude Code with the context it needs to generate organized, purposeful work. Combined with TDD methodology, this approach creates a development process that's both efficient and reliable.
The next time you start a new feature or project, resist the urge to jump straight into code. Instead, spend 15-30 minutes creating a planning document with Claude Code. The structured phases and todo lists it generates will not only guide your development but also integrate seamlessly with your existing project management workflow.
Remember: Great software isn't just coded—it's planned, tracked, and delivered with purpose.
For more on structuring your AI-assisted development workflow, see Taming GenAI Agents Like Claude Code with Test-Driven Development.