How to Write Features

This document defines how a human must write feature requirements for the LLM.

Apply naming rules from prompts/flavors/01-semantic-sort-naming.md.

1. Feature Purpose

• A feature defines a project capability, its behavior, and its requirements.
• A feature is stable project context that may be implemented by one or more tasks.
• A feature must not describe a single implementation step or TODO status update.

2. Feature File Location and Naming

• Feature requirements belong in prompts/features/.
• Feature numbers must be unique.
• Use the established feature name.
• Do not invent a feature name when an existing project name applies.

3. Feature Structure

Every feature must contain these sections in order:

# Feature: <feature name>
    
    ## Purpose
    
    Describe the capability and the problem it solves.
    
    ## Requirements
    
    List the mandatory behavior and constraints.
    
    ## Behavior
    
    * Describe externally observable behavior.
    
    ## Dependencies
    
    * List directly required features, or state `None`.

4. Requirement Rules

• Requirements must be specific, testable, and implementation-independent.
• Requirements must describe what the feature does, not how a task must implement it.
• Each requirement must be stated as a separate bullet.
• Do not include TODO status, task sequencing, or response-format instructions in a feature file.

5. Feature and Task Relationship

• A feature file defines capability requirements.
• A task requests a bounded change that implements, tests, documents, or modifies a feature.
• A task must explicitly reference every feature file whose requirements apply.
• A feature may be implemented by multiple tasks.
• A task may address multiple features only when it explicitly references each feature.

6. Feature Changes

• Modify an existing feature file when the capability requirements change.
• Create a new feature file when the project gains a distinct capability.
• Do not duplicate requirements across feature files.
• Update dependent tasks when a feature change makes their requirements or assumptions invalid.