I made a really big flowchart diagram of all of our services and how they interrelate by giving Claude Code the description of what I wanted starting at the entry point project and working its way through the entire system to the data ingestion point. I gave Claude my GitHub access token so it could look through or clone each repo it needed. I also had many of the projects already cloned in my workspace folder through years of working on the various projects.

Claude was able to determine the project, analyze the code, and infer the infrastructure. It worked through the projects as it went drawing a higher level diagram first. Then I iteratively asked for more detail around the sections I thought needed more detail.

This was just an experiment that I spent a few hours on. Months later I misplaced the mermaid markdown file so I asked Claude to reproduce the mermaid markdown from the png image so I could have it add more detail around another section that looked incorrect because it encapsulated the database and worker for one of the systems in a single box. The detail made the diagram in that area much more clear.

To me it is very good at writing/reading/reverse engineering mermaid diagrams.