I Tested Every 'Memory' Solution for AI Coding Assistants - Here's What Actually Works

Every AI coding session starts from scratch. You open Claude Code or Codex, and it has no idea that your team uses JWT with 15-minute expiry, that you migrated from REST to GraphQL last month, or that the payments service is the one thing you never touch on Fridays. You re-explain the same architecture decisions, the same conventions, the same constraints. Every single time. This is not a minor annoyance. It is compounding time loss. The first 5-10 minutes of every session is wasted on context that the assistant already learned yesterday. Over weeks, that adds up to hours.