Fission-AI/OpenSpec ? reverse-engineered prompt

I'm trying to build things with AI coding assistants, but it gets chaotic. The AI forgets the plan halfway through, and I have to repeat myself. I want you to build a simple tool to fix this.

It should be a command-line tool, written in TypeScript, that helps me and the AI agree on a plan before any code gets written. The workflow should be based on simple slash commands I can use in my chat. For example, I'd type /propose 'add a dark mode' and it would create a folder for that feature with some simple markdown files: a proposal, the specs, a technical design, and a task checklist.

Once the plan looks good, I'd use another command like /apply to tell the AI to execute the tasks. It should also have commands to archive old features to keep the project clean. Basically, it's a lightweight spec-driven development system that makes AI coding more predictable without being rigid and bureaucratic. Make sure it's installable via npm.