The $4.87 Spec: How Local Session Storage Cuts AI Costs by 89%

A simple file-based memory system for AI coding sessions turned a $45 multi-session rebuild into a single $4.87 conversation. Here's the architecture, the data, and why context management is the most undervalued problem in AI-assisted development. The Problem Nobody Talks About Every AI coding assistant has the same dirty secret: context evaporates. You spend 3 hours in a session with your AI pair programmer. You explore APIs, validate assumptions, make design decisions, discover edge cases. Then the session ends. Tomorrow, you start from zero. The next session costs just as much — not because the work is hard, but because the AI has to rediscover everything it already knew. Tracked across 53 sessions over 6 weeks on a platform engineering project. The waste was staggering. What Was Measured The setup: an AI coding assistant used for infrastructure automation — managing on-call schedules, incident response tooling, and platform operations across multiple cloud environments. The work is