[RFC] Modernize spec-kit with Bun, TypeScript, and Extensible Architecture

[amondnet]

🎯 Executive Summary

Propose a comprehensive modernization of spec-kit to create a cross-platform, testable, and extensible Spec-Driven Development framework using Bun and TypeScript.

📋 Problem Statement

Current Limitations

1. Platform Dependency:

   • Separate bash and PowerShell scripts required
   • Inconsistent behavior across platforms
   • Maintenance burden of dual implementations

2. Limited Testability:

   • Bash scripts are difficult to unit test
   • No test coverage for core functionality
   • Integration testing requires manual verification

3. Poor Extensibility:

   • Hard-coded behaviors in scripts
   • No plugin system for custom features
   • Templates are static with no transformation capabilities

4. Type Safety Issues:

   • No compile-time checks
   • Runtime errors only discovered during execution
   • Difficult to refactor safely

🚀 Proposed Solution

Architecture Overview

spec-kit/
├── packages/
│   ├── @spec-kit/core/           # Core functionality
│   ├── @spec-kit/cli/            # CLI interface
│   ├── @spec-kit/plugins/        # Plugin system
│   ├── @spec-kit/templates/      # Template engine
│   └── @spec-kit/scripts/        # Migrated scripts
├── plugins/                      # Built-in plugins
│   ├── git-workflow/
│   ├── github-integration/
│   └── ai-assistant/
├── templates/                    # Default templates
├── tests/                        # Integration tests
└── bun.lockb                     # Bun lockfile