uml-mcp

TikZ Diagrams

UML-MCP supports TikZ/PGF graphics via Kroki. You can render TikZ and LaTeX snippets to SVG, PDF, PNG, or JPEG without installing TeX locally.

Overview

Backend: Kroki (default). No local LaTeX installation required.
Optional: Local compilation with Docker; see Optional Docker below.
Output formats: SVG, PDF, PNG, JPEG.

Use diagram_type: "tikz" with the generate_uml or generate_diagram_url tools. The code parameter is your TikZ/LaTeX source (snippet or full document).

Available templates and examples

The TikZ module provides a template library and auto-wrapping:

Snippets: If you pass only \begin{tikzpicture}...\end{tikzpicture}, the server wraps it in a minimal standalone LaTeX document and infers required TikZ libraries where possible.
Full documents: If your code already contains \documentclass, it is sent as-is to Kroki.

Templates (via tools.kroki.tikz.TikZTemplateLibrary) include:

Template	Description
flowchart	Decision/process flowchart
graph	Simple node-and-edge graph
math_plot	2D function plot (pgfplots)
tree	Tree structure
automata	Finite state machine
geometry_circle	Circle and axes
mindmap_simple	Mind map
circuit_simple	Simple circuit (IEC)
coordinate_grid	XY grid
block_diagram	Input–Process–Output blocks

Example files are in examples/:

example-tikz-flowchart.tex, example-tikz-math.tex, example-tikz-graph.tex
example-tikz-automata.tex, example-tikz-tree.tex, example-tikz-3d.tex
example-tikz-mindmap.tex, example-tikz-circuit.tex, example-tikz-block.tex

Output format comparison

Format	Best for	Notes
SVG	Web, scaling	Vector, small size
PDF	Print, documents	Vector, high quality
PNG	Presentations, UI	Raster, good compatibility
JPEG	Photos, large areas	Raster, smaller files

Use output_format in the tool call (e.g. "svg", "pdf", "png", "jpeg").

Common patterns

Flowchart (uses shapes, arrows, positioning):

\begin{tikzpicture}[node distance=2cm]
  \node[rectangle, draw] (start) {Start};
  \node[diamond, draw, below of=start] (dec) {OK?};
  \draw[->] (start) -- (dec);
\end{tikzpicture}

Math plot (uses pgfplots):

\begin{tikzpicture}
  \begin{axis}[xlabel=$x$, ylabel=$f(x)$, grid=major]
    \addplot[blue, domain=-2:2] {x^2};
  \end{axis}
\end{tikzpicture}

Automata (uses automata, positioning):

\begin{tikzpicture}[shorten >=1pt, node distance=2cm]
  \node[state, initial] (q0) {$q_0$};
  \node[state, accepting, right of=q0] (q1) {$q_1$};
  \draw[->] (q0) to node {1} (q1);
\end{tikzpicture}

Tips for complex diagrams

Add \usetikzlibrary{...} in your code when you use features from a library; the server can also infer some libraries from common commands.
For pgfplots, the wrapper adds \usepackage{pgfplots} and \pgfplotsset{compat=1.18} when needed.
Use a full standalone document if you need custom packages or fonts (e.g. \documentclass{standalone}\usepackage{tikz}\usepackage{pgfplots}...).

Local vs Kroki rendering

Aspect	Kroki (default)	Local (Docker)
Setup	None	Docker build/run
Network	Required	Optional
Custom TeX	Kroki’s environment	Your image
Use case	Most diagrams	Offline or custom deps

To use optional local compilation, set USE_LOCAL_LATEX=true and use the LaTeX Docker setup under tools/docker/ (see Optional Docker).

Optional Docker

For local LaTeX/TikZ compilation without Kroki:

Build and start the container from the project root:

docker compose -f tools/docker/docker-compose.latex.yml build
docker compose -f tools/docker/docker-compose.latex.yml up -d

Compile a .tex file inside the container (e.g. from examples/):

docker exec -it uml-mcp-latex xelatex -interaction=nonstopmode /workspace/examples/example-tikz-flowchart.tex

See tools/docker/README.md for details and volume mounts.

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