Diagram types¶

UML-MCP exposes 30+ diagram types through a single tool surface. This page is the canonical catalog; the same data is served at runtime via the uml://types, uml://formats, and uml://capabilities resources.

Live data

For the authoritative list at runtime, ask the server: tools/call list_diagram_types or resources/read uml://types. The static tables below match the values defined in mcp_core/core/config.py.

UML (PlantUML family)¶

All UML types are rendered through the PlantUML backend on Kroki.

`diagram_type`	Description	Output formats
`class`	Classes, attributes, methods, relationships	`png`, `svg`, `pdf`, `txt`, `base64`
`sequence`	Object interactions arranged in time	`png`, `svg`, `pdf`, `txt`, `base64`
`activity`	Workflows and business processes	`png`, `svg`, `pdf`, `txt`, `base64`
`usecase`	System functionality and actors	`png`, `svg`, `pdf`, `txt`, `base64`
`state`	Lifecycle states of an object	`png`, `svg`, `pdf`, `txt`, `base64`
`component`	Components and dependencies	`png`, `svg`, `pdf`, `txt`, `base64`
`deployment`	Physical architecture	`png`, `svg`, `pdf`, `txt`, `base64`
`object`	Class instances and their relationships	`png`, `svg`, `pdf`, `txt`, `base64`
`plantuml`	Raw PlantUML source (any diagram kind)	`png`, `svg`, `pdf`, `txt`, `base64`
`c4plantuml`	C4 model diagrams via PlantUML includes	`png`, `svg`, `pdf`, `txt`, `base64`

UML page with examples

General-purpose¶

`diagram_type`	Backend	Description	Output formats
`mermaid`	Mermaid	Browser-native flowchart, sequence, class, state, Gantt, ER, pie	`svg`, `png`
`d2`	D2	Modern declarative diagram language	`svg`
`graphviz`	Graphviz	Classic graph visualization (DOT)	`png`, `svg`, `pdf`, `jpeg`
`erd`	erd	Entity-relationship diagrams	`png`, `svg`, `jpeg`, `pdf`
`bpmn`	BPMN	Business Process Model & Notation	`svg`
`dbml`	DBML	Database Markup Language schemas	`svg`
`nomnoml`	nomnoml	UML-style diagrams from shorthand syntax	`svg`

D2 · Graphviz · More backends overview · Mermaid live examples

Snippets: ERD · DBML · BlockDiag · BPMN XML · C4 PlantUML · Structurizr · Specialty types

blockdiag family¶

`diagram_type`	Description	Output formats
`blockdiag`	Simple block diagrams	`png`, `svg`, `pdf`
`seqdiag`	Sequence diagrams (blockdiag family)	`png`, `svg`, `pdf`
`actdiag`	Activity / workflow diagrams	`png`, `svg`, `pdf`
`nwdiag`	Network diagrams	`png`, `svg`, `pdf`
`packetdiag`	Network packet layouts	`png`, `svg`, `pdf`
`rackdiag`	Rack and server layouts	`png`, `svg`, `pdf`

BlockDiag family snippets

Specialized¶

`diagram_type`	Description	Output formats
`tikz`	TikZ/PGF graphics (LaTeX)	`svg`, `pdf`, `png`, `jpeg`
`bytefield`	Binary protocol and byte layout	`svg`
`ditaa`	ASCII-art diagrams	`png`, `svg`
`excalidraw`	Whiteboard-style sketches	`svg`
`pikchr`	Pikchr diagram scripting language	`svg`
`structurizr`	C4 and architecture DSL	`png`, `svg`, `pdf`, `txt`, `base64`
`svgbob`	ASCII art to SVG	`svg`
`symbolator`	Digital logic / schematic symbols	(varies)
`vega` / `vegalite`	Visualization grammars	(varies)
`wavedrom`	Waveform and digital timing	`svg`
`wireviz`	Cable and wiring diagrams	(varies)

TikZ page · Specialty types

Picking a `diagram_type`¶

flowchart TD
    Start([What do you want to draw?]) --> Q1{Software UML?}
    Q1 -- yes --> UML[Use class / sequence / activity / usecase / state / component / deployment / object]
    Q1 -- no  --> Q2{Process or workflow?}
    Q2 -- yes --> Proc[Use activity, mermaid flowchart, bpmn, or blockdiag]
    Q2 -- no  --> Q3{Architecture / C4?}
    Q3 -- yes --> Arch[Use c4plantuml or structurizr]
    Q3 -- no  --> Q4{Data / schema?}
    Q4 -- yes --> Data[Use erd or dbml]
    Q4 -- no  --> Q5{Math / scientific?}
    Q5 -- yes --> Sci[Use tikz or graphviz]
    Q5 -- no  --> Other[Use mermaid for fallback or browse the catalog]

Format support varies

Not every diagram type supports every output format. validate_uml returns a clear error if you ask for an unsupported output_format; or check uml://formats first.