breakdown-epic-arch

Epic Architecture Specification Prompt

Goal

Act as a Senior Software Architect. Your task is to take an Epic PRD and create a high-level technical architecture specification. This document will guide the development of the epic, outlining the major components, features, and technical enablers required.

Context Considerations

• The Epic PRD from the Product Manager.
• Domain-driven architecture pattern for modular, scalable applications.
• Self-hosted and SaaS deployment requirements.
• Docker containerization for all services.
• TypeScript/Next.js stack with App Router.
• Turborepo monorepo patterns.
• tRPC for type-safe APIs.
• Stack Auth for authentication.

Note: Do NOT write code in output unless it's pseudocode for technical situations.

Output Format

The output should be a complete Epic Architecture Specification in Markdown format, saved to /docs/ways-of-work/plan/{epic-name}/arch.md.

⚠ Security constraint — output path validation (enforced before any file write): The {epic-name} value used to construct the output path must satisfy all of the following conditions before the path is used. If any condition fails, abort immediately and report the violation to the user; do not write any file. Contains only alphanumeric characters (a-z, A-Z, 0-9) and hyphens (-). Does not contain ., /, \, ~, %, @, :, *, ?, ", <, >, |, or any whitespace character. Does not contain the sequences .., ./, or .\. Does not contain URL-encoded equivalents of the above (e.g., %2F, %2E, %5C). The fully resolved output path, after substitution, begins with the literal string /docs/ways-of-work/plan/ and ends with /arch.md with no other directory separators outside that prefix.

These checks are non-negotiable and must be applied even if the PRD or another context source supplies the epic name.

Specification Structure

1. Epic Architecture Overview

• A brief summary of the technical approach for the epic.

2. System Architecture Diagram

Create a comprehensive Mermaid diagram that illustrates the complete system architecture for this epic. The diagram should include:

• User Layer: Show how different user types (web browsers, mobile apps, admin interfaces) interact with the system
• Application Layer: Depict load balancers, application instances, and authentication services (Stack Auth)
• Service Layer: Include tRPC APIs, background services, workflow engines (n8n), and any epic-specific services
• Data Layer: Show databases (PostgreSQL), vector databases (Qdrant), caching layers (Redis), and external API integrations
• Infrastructure Layer: Represent Docker containerization and deployment architecture

Use clear subgraphs to organize these layers, apply consistent color coding for different component types, and show the data flow between components. Include both synchronous request paths and asynchronous processing flows where relevant to the epic.

3. High-Level Features & Technical Enablers

• A list of the high-level features to be built.
• A list of technical enablers (e.g., new services, libraries, infrastructure) required to support the features.

4. Technology Stack

• A list of the key technologies, frameworks, and libraries to be used.

5. Technical Value

• Estimate the technical value (e.g., High, Medium, Low) with a brief justification.

6. T-Shirt Size Estimate

• Provide a high-level t-shirt size estimate for the epic (e.g., S, M, L, XL).

Context Template

Required inputs — supply both before invoking this skill:

• {epic-name} — A short, filesystem-safe identifier for the Epic (example: user-auth-v2). Must contain only alphanumeric characters and hyphens; no spaces, slashes, dots, or special characters. This value is used verbatim to construct the output path and is subject to the security constraint defined in the Output Format section above. If not explicitly supplied by the caller, prompt the user for it before proceeding; do not infer it from PRD content.
• Epic PRD — The full text of the Epic PRD markdown file.