Why I built a Local-First Codebase Visualizer to save 80% on AI Tokens

As developers, we've all been there: you join a new project or inherit a legacy "spaghetti" codebase, and it takes days (or weeks) just to understand the architecture. With the rise of LLMs, we thought the problem was solved. But then came the "Context Window Fatigue": Sending a whole repo to a cloud AI is expensive. Uploading proprietary code to a third-party server is a privacy nightmare. Most AI assistants don't "see" the big picture (the architecture). That's why I spent the last few months building Carto Explorer. The Concept: Local-First Intelligence I wanted a tool that lived on my machine, indexed my code in seconds, and only talked to the AI when it truly understood the context. The Tech Stack Backend: Rust (using Tauri v2). I chose Rust for its raw performance in file indexing and safety. Frontend: React with Tailwind CSS. Visuals: React Flow for the interactive architecture maps. AI: Gemini 2.0 (Pro & Flash) via user-provided API keys. How it works (The Technical Bits) 1