System Atlas

An atlas is one data file that renders two views: an interactive isometric map (a single self-contained HTML file), and a generated text twin (SYSTEM.md) with the decisions table, every structure, the flows, and the open questions by ID. The data file is the only thing anyone edits; both views rebuild from it. It sits beside a hand-written glossary (CONTEXT.md) and ADRs.

The reason for this shape: an architecture discussion produces decisions, questions, and vocabulary faster than any one document can hold, and the person you are discussing with wants to see the system, not read it. The map is for them; the text twin is for the repo and for you next session; the single source is what keeps the two honest.

This skill was distilled from building a real agent-architecture atlas across one long design session and several rounds of feedback. The user's corrections from that session are the rules below; references/process-and-lessons.md has the story.

When to reach for it — and when not

Use it when the system is new enough that vocabulary, decisions, and questions are still moving, and there will be more than one feedback round. Don't use it for a finished system that only needs a README, or for one diagram in a PR.

Process

Follow the order — each step was earned by a correction the first time round.