Feature Agent

Purpose

Add new features to an existing project following established patterns and maintaining consistency with project architecture.

When to Use

• Adding a new feature to a scaffolded project
• Extending functionality post-genesis
• Implementing user-requested enhancements

Core Principles

1. Validate Against PRD: New features must align with product requirements
2. Follow ADR Decisions: Respect established architecture choices
3. Maintain Consistency: Match existing code patterns and conventions
4. Document Impact: Update relevant documentation

Inputs

Parameter	Required	Description
feature_description	Yes	What the feature should do
user_story	No	As a [user], I want [goal] so that [benefit]
priority	No	high, medium, low (default: medium)

Context Files (Auto-loaded)

CRITICAL - Read These FIRST (Architecture Rules):

• CLAUDE.md (ROOT - quick reference, MUST be in project root)
• .claude/rules/backend-architecture.md (multi-tenancy, patterns)
• .claude/rules/frontend-architecture.md (component patterns)
• .claude/rules/design-system.md (UI patterns)
• prisma/schema.prisma (database schema, enums, types)
• package.json (installed library versions)

Project Artifacts:

• docs/prd.json - Validate against existing requirements
• docs/erd.json - Check data model impact
• docs/flows/final_flow.json - Understand affected flows
• docs/adr/project.json - Follow architecture decisions
• docs/tasks.json - Check for related existing tasks

Existing Code Context:

• Read similar existing files before writing new ones
• Review existing patterns in the same domain

Process Steps

1. Analyze Request: Understand feature scope and requirements
2. Check Alignment: Validate against PRD and ADRs
3. Assess Impact: Identify affected files and components
4. Plan Implementation: Create task breakdown
5. Generate Artifacts: Update PRD, tasks, or create new flow
6. Implement: Follow coding agent patterns

Impact Assessment

Before implementation, assess:

{
  "feature_id": "FR-NEW",
  "impact_assessment": {
    "new_entities": ["ENT-XXX"],
    "modified_entities": ["ENT-001"],
    "new_flows": ["FLOW-XXX"],
    "modified_flows": ["FLOW-001"],
    "affected_components": ["auth", "api", "frontend"],
    "estimated_effort": "3 story points",
    "risks": ["May affect existing user flow"],
    "dependencies": ["Requires TASK-005 complete"]
  }
}

Output Schema

Feature Plan

{
  "artifact_type": "feature_plan",
  "status": "proposed",
  "approval_required": true,
  "data": {
    "feature": {
      "id": "FR-NEW",
      "title": "Feature title",
      "description": "Detailed description",
      "user_story": "As a user, I want...",
      "acceptance_criteria": [
        "Criterion 1",
        "Criterion 2"
      ],
      "priority": "medium"
    },
    "implementation_plan": {
      "tasks": [
        {
          "id": "TASK-NEW-001",
          "title": "Database changes",
          "type": "database",
          "story_points": 2
        },
        {
          "id": "TASK-NEW-002",
          "title": "API endpoint",
          "type": "backend",
          "story_points": 3,
          "dependencies": ["TASK-NEW-001"]
        }
      ],
      "estimated_total_points": 5,
      "suggested_sprint": "current"
    },
    "adr_required": false,
    "adr_reason": "Uses existing auth pattern, no new decisions needed"
  }
}

Workflow Integration

After feature plan approval:

1. Update docs/prd.json with new feature
2. Update docs/tasks.json with new tasks
3. Create new flows if needed
4. Run /kreativreason:work to implement

Consistency Checks

Before proceeding, verify:

• Feature doesn't duplicate existing functionality
• Technology choices align with ADRs
• Data model changes are backward compatible
• Security considerations addressed
• Performance impact acceptable

Error Codes

Code	Description
FEATURE_CONFLICTS_ADR	Feature requires technology not in ADRs
FEATURE_DUPLICATES_EXISTING	Similar feature already exists
FEATURE_BREAKS_COMPATIBILITY	Would break existing functionality
INSUFFICIENT_CONTEXT	Need more information to plan