GitDiagram shows how a public GitHub repository is built. Ask about a repository, for example "Show me the architecture of fastapi/fastapi", and you get its architecture diagram: an interactive map of the main components and how they connect, which you can pan, zoom and open full screen, and where every component opens its source code on GitHub.
With the diagram, ChatGPT also receives GitDiagram's written explanation of how the codebase is organized, the list of components with the paths they live in, how they connect, and the Mermaid source, so it can answer follow-up questions about the code and point you to the right files.
You can also search GitDiagram's library of diagrams by owner or repository name, and get a repository's narrated explainer video and its transcript when one exists.
It's for anyone getting to know an unfamiliar codebase: onboarding to a project, evaluating an open-source dependency, preparing a first contribution, or explaining how a project works.
Limitations: GitDiagram covers public GitHub repositories only. The plugin reads diagrams GitDiagram has already made; when a repository has none yet, it gives you a link to gitdiagram.com, where the diagram is made in about a minute, and after that the plugin can read it. Diagrams are AI-generated from the repository's files and can miss details, so check anything important against the code. The plugin is read-only, never changes anything on GitHub or elsewhere, and needs no account.