uml-mcp: Skill for Claude Code

PlantUML and C4

Follow skill://uml-mcp-diagrams/SKILL.md. Discover c4plantuml or the relevant PlantUML type. Use Kroki first unless the user selects a different rendering service. Maintain the same people, systems and directed relationships when converting an existing architecture; do not invent a new architecture per format.

There is no assumed C4_Code library. Level 4 is optional unless requested; use real source evidence or label it as a proposed design. For full examples, read docs/diagrams/c4-views.md in the repository.

@startuml Containers
!include <C4/C4_Container>
LAYOUT_LEFT_RIGHT()
title Web application containers
Person(user, "User")
Container(web, "Frontend", "React")
Container(api, "Backend", "HTTP API")
ContainerDb(db, "Database", "SQL")
Rel(user, web, "Uses", "HTTPS")
Rel(web, api, "Calls", "JSON / HTTPS")
Rel(api, db, "Reads and writes", "SQL")
@enduml

Keep @startuml (including any optional diagram name) on its own line. Use actual PlantUML themes such as plain, cerulean and cyborg. Put !theme on a separate line; never use !theme light or append the diagram name to it. Prefer standard-library includes to network include URLs.

Validate and then render each view as SVG. Check for renderer error pages, missing text and invisible labels at all requested levels. A successful batch response does not prove each item is usable. Inspect individual errors and retry only failed views; retain successful ones. Copy only fresh returned links. The PlantUML playground should be returned for C4 too, even with Kroki rendering. Use the App's SVG download for sharp output; PNG export rasterizes the vector with bundled fonts. Re-rendering PNG as SVG must update the active item without losing its labels, source or other batch entries.