c4-modellisted
Install: claude install-skill cwschroeder/buzz-agent-comms
# C4 model — diagramming a software architecture
This skill is vendored under the MIT license, copyright Cherif Toujeni. The
license is stored beside this file and must stay with any copy. It owns
`docs/ARCHITECTURE.md` together with `arc42-documentation`, as the project
file set in `buzz-team-communication` states. The only change from the
original is this frontmatter: the description is now a block scalar, because
the colons inside it made the original line invalid YAML. The wording is
unchanged.
Simon Brown's C4 model ([`c4model.com`](https://c4model.com)) describes a software architecture through four hierarchical levels of abstraction. This skill covers the full cycle around a C4 diagram: design, retro-documentation, review, update.
## The 4 levels
| Level | Diagram | Mermaid | Zoom | Audience |
|---|---|---|---|---|
| 1 | **Context** | `C4Context` | System + actors / external systems | Everyone (technical and non-technical) |
| 2 | **Container** | `C4Container` | Applications, services, internal data stores | Technical team (dev, ops, architecture) |
| 3 | **Component** | `C4Component` | Internal components of a container | Developers of that container |
| 4 | **Code** | `classDiagram` (UML) | Classes/functions of a component | Developers (often generated by the IDE) |
**Simon Brown's golden rule**: *"Context + Container diagrams are sufficient for most software development teams."* Only generate levels 3 and 4 when the user explicitly asks for them or when they b