tdd-design-detail

Convert a high-level design.md into a detailed-design.md with modules, interfaces, and test boundaries.

4|1|Updated Apr 8, 2026
One-click install
npx skills add https://github.com/CurtisThe/three-pillars-plugin --skill tdd-design-detail
Or copy as Structured Prompt for Agent
Please help me install this Agent Skill.
Skill: tdd-design-detail
Source: https://github.com/CurtisThe/three-pillars-plugin/tree/main/skills/tdd-design-detail
Command: npx skills add https://github.com/CurtisThe/three-pillars-plugin --skill tdd-design-detail

SYSTEM DOCUMENTATION & REQUIREMENTS

What problem does it solve?

Converts a high-level design.md into a concrete, implementation-ready detailed-design.md that maps entities and behaviors to modules, interfaces, and test boundaries.

Core Features & Use Cases

  • Translates an existing design into a structured detailed design, including module structure, interfaces, data flow, and test boundaries.
  • Guides collaborative planning with preflight checks, design validation, and an executable implementation plan.
  • Produces a reproducible artifact at docs/tdd-designs/<design-name>/detailed-design.md for future reference and auditing.

Quick Start

Run /tdd-design-detail <design-name> to generate docs/tdd-designs/<design-name>/detailed-design.md from your existing design.md

Frequently Asked Questions about tdd-design-detail

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I convert a high-level design document into a test-ready detailed design?

Converting a high-level design into a detailed design involves mapping entities and behaviors to modules, interfaces, and test boundaries. This Skill generates a reproducible detailed-design.md artifact from your existing design.md file.

What is the best way to structure module interfaces and test boundaries for a new software architecture?

Structuring module interfaces and test boundaries is best handled by generating a detailed-design document that translates high-level architecture into concrete implementation plans, ensuring reproducible mapping between entities and modules.

Do I need an existing design.md file before generating a detailed design document?

Yes, an existing design.md file is required. The Skill performs collaborative preflight checks, reads your current high-level design, and outputs the detailed design to docs/tdd-designs/<design-name>/detailed-design.md.

How does detailed design generation handle implementation planning and documentation?

Detailed design generation handles implementation planning by validating the existing design and producing an executable implementation plan alongside the detailed-design.md, covering module structure, interfaces, and data flow.

Can I use this detailed design approach for collaborative architecture validation?

Yes, you can use this approach for collaborative architecture validation. The process includes preflight checks and design validation to guide team planning before outputting the final detailed design artifact.

What are the limitations of generating a detailed design from an existing high-level design?

A limitation of generating a detailed design is its strict dependency on a pre-existing high-level design.md file; without a valid initial design, the Skill cannot map modules or generate the implementation plan.