/senior-architect

name: "senior-architect"
description: "System architecture decisions with a written rationale: monolith vs microservices, database choice, scaling limits, ADRs, Mermaid diagrams. Load whenever the user asks should we split, which database, will it scale, or wants an ADR."

Senior Architect

Architecture design and analysis tools for making informed technical decisions.

Table of Contents

• [Quick Start](#quick-start)
• [Tools Overview](#tools-overview)
• [Architecture Diagram Generator](#1-architecture-diagram-generator)
• [Dependency Analyzer](#2-dependency-analyzer)
• [Project Architect](#3-project-architect)
• [Decision Workflows](#decision-workflows)
• [Database Selection](#database-selection-workflow)
• [Architecture Pattern Selection](#architecture-pattern-selection-workflow)
• [Monolith vs Microservices](#monolith-vs-microservices-decision)
• [Reference Documentation](#reference-documentation)
• [Tech Stack Coverage](#tech-stack-coverage)
• [Common Commands](#common-commands)

---

Quick Start

# Generate architecture diagram from project
python scripts/architecture_diagram_generator.py ./my-project --format mermaid

# Analyze dependencies for issues
python scripts/dependency_analyzer.py ./my-project --output json

# Get architecture assessment
python scripts/project_architect.py ./my-project --verbose

---

Tools Overview

1. Architecture Diagram Generator

Generates architecture diagrams from project structure in multiple formats.

**Solves:** "I need to visualize my system architecture for documentation or team discussion"

**Input:** Project directory path **Output:** Diagram code (Mermaid, PlantUML, or ASCII)

**Supported diagram types:**

• `component` - Shows modules and their relationships
• `layer` - Shows architectural layers (presentation, business, data)
• `deployment` - Shows deployment topology

**Usage:**

# Mermaid format (default)
python scripts/architecture_diagram_generator.py ./project --format mermaid --type component

# PlantUML format
python scripts/architecture_diagram_generator.py ./project --format plantuml --type layer

# ASCII format (terminal-friendly)
python scripts/architecture_diagram_generator.py ./project --format ascii

# Save to file
python scripts/architecture_diagram_generator.py ./project -o architecture.md

**Example output (Mermaid):**

graph TD
    A[API Gateway] --> B[Auth Service]
    A --> C[User Service]
    B --> D[(PostgreSQL)]
    C --> D

---

2. Dependency Analyzer

Analyzes project dependencies for coupling, circular dependencies, and outdated packages.

**Solves:** "I need to understand my dependency tree and identify potential issues"

**Input:** Project directory path **Output:** Analysis report (JSON or human-readable)

**Analyzes:**

• Dependency tree (direct and transitive)
• Circular dependencies between modules
• Coupling score (0-100)
• Outdated packages

**Supported package managers:**

• npm/yarn (`package.json`)
• Python (`requirements.txt`, `pyproject.toml`)
• Go (`go.mod`)
• Rust (`Cargo.toml`)

**Usage:**

# Human-readable report
python scripts/dependency_analyzer.py ./project

# JSON output for CI/CD integration
python scripts/dependency_analyzer.py ./project --output json

# Check only for circular dependencies
python scripts/dependency_analyzer.py ./project --check circular

# Verbose mode with recommendations
python scripts/dependency_analyzer.py ./project --verbose

**Example output:**

Dependency Analysis Report
==========================
Total dependencies: 47 (32 direct, 15 transitive)
Coupling score: 72/100 (moderate)

Issues found:
- CIRCULAR: auth → user → permissions → auth
- OUTDATED: lodash 4.17.15 → 4.17.21 (security)

Recommendations:
1. Extract shared interface to break circular dependency
2. Update lodash to fix CVE-2020-8203

---

3. Project Architect

Analyzes project structure and detects architectural patterns, code smells, and improvement opportunities.

**Solves:** "I want to understand the current architecture and identify areas for improvement"

**Input:** Project directory path **Output:** Architecture assessment report

**Detects:**

• Architectural patterns (MVC, layered, hexagonal, microservices indicators)
• Code organization issues (god classes, mixed concerns)
• Layer violations
• Missing architectural components

**Usage:**

# Full assessment
python scripts/project_architect.py ./project

# Verbose with detailed recommendations
python scripts/project_architect.py ./project --verbose

# JSON output
python scripts/project_architect.py ./project --output json

# Check specific aspect
python scripts/project_architect.py ./project --check layers

**Example output:**

Architecture Assessment
=======================
Detected pattern: Layered Architecture (confidence: 85%)

Structure analysis:
  ✓ controllers/  - Presentation layer detected
  ✓ services/     - Business logic layer detected
  ✓ repositories/ - Data access layer detected
  ⚠ models/       - Mixed domain and DTOs

Issues:
- LARGE FILE: UserService.ts (1,847 lines) - consider splitting
- MIXED CONCERNS: PaymentController contains business logic

Recommendations:
1. Split UserService into focused services
2. Move business logic from controllers to services
3. Separate domain models from DTOs

---

Decision Workflows

Database Selection Workflow

Use when choosing a database for a new project or migrating existing data.

**Step 1: Identify data characteristics** | Characteristic | Points to SQL | Points to NoSQL | |----------------|---------------|-----------------| | Structured with relationships | ✓ | | | ACID transactions required | ✓ | | | Flexible/evolving schema | | ✓ | | Document-oriented data | | ✓ | | Time-series data | | ✓ (specialized) |

**Step 2: Evaluate scale requirements**

• <1M records, single region → PostgreSQL or MySQL
• 1M-100M records, read-heavy → PostgreSQL with read replicas
• >100M rec