You installed five skills off the marketplace. They each work in isolation. You ask the launch-thread skill to draft a release post, and it doesn't know what your shipping-checklist skill already wrote into your release notes. So you re-explain the project to it. Every. Time.

This is the most common failure mode I see in Claude Code setups, and it isn't a model problem. It's a file convention problem.

Skills are markdown prompts. A workflow OS is a set of skills that read each other's outputs. The difference between "I have six skills" and "I have a workflow" is exactly one document: the spec for which files each skill writes to and reads from.

I shipped a v0.1 of that spec this morning, free, MIT-licensed, fork it: agentstackhq.net/spec/file-conventions.md .

Here's what's in it and why it works.

The pattern problem

A skill in Claude Code is a SKILL.md file with a trigger phrase and a prompt.…