Feature Documentation

Beyond Freestyle Enhancement Docs

While enhancement docs capture future possibilities, feature documentation provides a systematic approach to planning, validating, and implementing new functionality via AI. This structured method prevents scope creep, feature collisions, and half-baked implementations.

The Feature Lifecycle Structure

devdocs/features/
    planned/
      feat_1_user_authentication/
        desc.md
        implementation_plan.md
        compatibility_check.md
        test_scenarios.md

    finished/
          feat_0_debug_output/
            desc.md
            implementation_plan.md
            compatibility_check.md
            test_scenarios.md
            implementation_notes.md
  

Core Documentation Files

1. desc.md - Feature Description

Defines WHAT and WHY:

• Clear problem statement
• User value proposition
• Success criteria
• Scope boundaries

2. implementation_plan.md - Technical Approach

Details HOW to build :

Consists of :

1. High level plan summary in bullet points
2. Full implementation plan

3. compatibility_check.md - Impact Analysis

Identifies Compatibility ISSUES, RISKS and CONFLICTS with respect to whole codebase worklogic :

• Existing features that might break
• Performance implications
• API contract changes
• Database schema impacts
• Security considerations

4. test_scenarios.md - Verification Strategy

Defines how we will KNOW it works (mid level technicality). This is a doc which describes testing logic not the test document itself

answers: 
   1. How this feature can be triggered in various ways in various codebase levels (from minimal run to bigger scope) and  How this feature should result in each scenario

5. Implementation_notes.md

 No feature will be implemented %100 correct the first time. Implementing it also uncovers new unknown issues 
 and requires various fixes. This documentation is storing that knowledge in minimal format. 

Step 1: Initial Capture

When you discover a feature need, create the basic structure:

devdocs/features/planned/feat_X_feature_name/
 desc.md              # Write this first
 implementation_plan.md   # Draft initial approach

Step 2: Validation

Before implementation, complete the analysis:

 compatibility_check.md   # What might break?
 dependencies.md          # What's needed first?
 test_scenarios.md        # How do we verify?

Step 3: Safety Planning

For production-ready features, add:

 rollback_plan.md         # How to undo?
 impacts.md               # What else changes?

Step 4: Implementation

When ready to build:

1. Move to active development
2. Use docs as AI context
3. Update plans as you learn

Step 5: Completion

After implementation:

1. Add implementation_notes.md documenting what actually happened
2. Move entire folder to finished/
3. Keep for future reference

AI Prompt Template for Feature Planning

I want to add a new feature: [FEATURE NAME]

Please help me create comprehensive feature documentation:

1. Read the current codebase structure
2. Create devdocs/features/planned/[FEATURE_NAME]/desc.md
   - Problem statement
   - User value
   - Success criteria
   - Scope boundaries

3. Create implementation_plan.md
   - Required architecture changes
   - New components needed
   - Integration approach
   - Implementation steps

4. Create compatibility_check.md
   - Analyze impact on existing features
   - Check for conflicts
   - Performance implications
   - Security considerations

5. Create test_scenarios.md
   - Happy path tests
   - Edge cases
   - Error conditions
   - Acceptance criteria

6. Create dependencies.md
   - Technical prerequisites
   - Feature dependencies
   - External requirements

7. Create rollback_plan.md
   - Feature flag approach
   - Database rollback strategy
   - Safe deployment plan

Benefits of Structured Feature Documentation

For Developers

• Clear implementation path
• No forgotten edge cases
• Confidence in rollback ability
• Prevents rework from poor planning

For AI Collaboration

• Complete context for implementation
• Understands constraints and risks
• Can generate comprehensive tests
• Avoids breaking existing features

For Project Management

• Visual progress tracking (planned � finished)
• Clear feature history
• Dependency management
• Risk assessment before starting

When to Use Feature Docs vs Enhancement Docs

Use Feature Documentation When:

• Feature has clear requirements
• Implementation will take > 1 day
• Multiple components affected
• Production deployment planned
• Other features depend on it

Use Enhancement Docs When:

• Idea is still forming
• Nice-to-have improvements
• Experimental features
• Future possibilities
• Architecture musings

Best Practices

1. Start lightweight - Don’t over-document features that might not happen
2. Evolve as needed - Add detail as features move toward implementation
3. Keep it current - Update plans when you learn new information
4. Learn from finished - Review completed features to improve planning
5. Prune regularly - Delete abandoned feature plans to reduce noise

Example: Complete Feature Documentation

devdocs/features/planned/feat_3_api_rate_limiting/
 desc.md
   "Prevent API abuse by limiting requests per user per minute"
 implementation_plan.md
   "Add middleware, use Redis for counters, configurable limits"
 compatibility_check.md
   "All API endpoints affected, 10ms latency added per request"
 test_scenarios.md
   "Test limits, resets, exemptions, distributed scenarios"
 dependencies.md
   "Requires Redis, user identification system"
 rollback_plan.md
   "Feature flag ENABLE_RATE_LIMIT, graceful degradation"
 impacts.md
    "Monitoring needed, customer support docs, API docs update"

This structured approach transforms vague feature ideas into implementation-ready specifications, reducing risk and improving delivery speed.