The Problem
Legacy code is everywhere. Companies have millions of lines of COBOL running critical systems, PHP 5 powering old websites, and Flash ActionScript in archived projects. Modernizing this code manually is tedious, error-prone, and expensive. What if AI could do it automatically?
The Solution: AI Necromancer
AI Necromancer is a web app that "resurrects" dead code using a multi-agent AI system:
The Archaeologist analyzes legacy code to detect language, purpose, and issues
The Necromancer transforms code to modern syntax or translates it to a new language
The Chronicler generates documentation explaining the transformation
Upload a ZIP file of legacy code, select your target language (Python, JavaScript, TypeScript, Rust, or Go), and watch as AI modernizes every file with detailed explanations.
Building with Kiro
The entire application - 40+ files, full-stack React and Express, OpenAI integration, batch processing, error handling, and comprehensive documentation - was built in one session with Kiro AI. Here's how:
Conversational Development
I treated Kiro like a pair programming partner. Instead of writing detailed specs upfront, I'd say things like "add ZIP file extraction" or "the API is returning 429 errors, fix it." Kiro would understand the context, diagnose the problem, and implement a complete solution across frontend and backend.
Intelligent Problem Solving
The most impressive moment was implementing the fallback mode. When I mentioned users should see API quota errors and choose fallback mode, Kiro generated an entire system: error detection banner, backend status codes, frontend error parsing, pause/resume logic, and visual indicators. It understood the full error flow without me specifying every detail.
Steering for Consistency
I created a steering document at .kiro/steering/necromancer.md that established the "necromancer" theme and technical constraints. This meant Kiro automatically maintained consistent naming (Archaeologist, Necromancer, Chronicler), followed the client-server architecture, and never suggested exposing API keys in the browser. The steering doc acted like persistent memory across conversations.
Rate Limiting Intelligence
When I mentioned OpenAI's rate limits (3 RPM for free tier, 500 RPM for paid), Kiro automatically implemented configurable rate limiting that adjusts from 20 seconds to 120ms based on environment variables. It even generated detailed documentation explaining the math and cost implications.
Technical Highlights
Frontend: React with Framer Motion for animations, JSZip for file handling, and a dark "Frankenstein lab" theme with lightning effects
Backend: Express server with OpenAI GPT-4o-mini integration, intelligent rate limiting, and graceful fallback when API limits are hit
Smart Features:
Automatic file extension changes (.cob → .py when translating to Python)
Preserves documentation files (.md, .json keep original extensions)
Batch processing with progress tracking
Three "vibe" modes: Necromancer (dramatic), Mentor (educational), Professional (concise)
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