@diagrammo/dgmo-mcp

Turn a conversation into a real diagram — without leaving your AI tool.

This MCP server gives Claude (and any MCP-compatible AI tool) the ability to render sequence diagrams, flowcharts, ER diagrams, C4 architecture, gantt charts, and 40+ other chart types from concise text markup — then hand the result off to a full editor for refinement. Ask for a diagram in chat; get a real one back.

What you can do

Ask in plain language — "diagram the auth flow as a sequence", "chart the Q3 plan as a gantt", "draw our services as a C4 diagram" — and Claude writes the markup and renders it. The markup stays readable and diffable:

flowchart Mutiny Resolution
direction-tb

[Sail]     Set sail under the captain
{Trouble?} Discontent in the crew?
{Vote}     Crew vote called
[Mutiny]   Seize the ship

(Sail) -> (Trouble?)
(Trouble?) -Yes-> (Vote)
(Vote) -Mutiny-> (Mutiny)

→ renders to the flowchart above. All rendering happens locally — no diagram data leaves your machine.

Tools

Tool	What it does	Over HTTP
render_diagram	Render DGMO markup to SVG or PNG	yes
validate_diagram	Check markup and report parse errors, without rendering	yes
suggest_chart_type	Suggest the chart types that fit a description	yes
list_chart_types	List all supported chart types, marking the beta ones	yes
get_language_reference	Get DGMO syntax documentation for accurate generation	yes
get_examples	Fetch worked examples for a chart type	yes
share_diagram	Get a shareable diagrammo.app URL — hand your diagram to the web editor	yes
open_in_app	Open the diagram straight into the Diagrammo desktop app for editing	no
check_app_installed	Report whether the desktop app is installed	no
preview_diagram	Render one or more diagrams and open an HTML preview in the browser	no
generate_report	Build a polished multi-section HTML report with ToC and optional source	no
put_space_diagram	Write a diagram into a Diagrammo Cloud space, by folder and title	yes
get_space_diagram	Read a diagram from a Cloud space, by id or by folder and title	yes
list_space_diagrams	List every diagram in a Cloud space	yes

The three space tools send the diagram to Diagrammo Cloud. They need a space API key (minted on the Diagrammo account page) as DGMO_API_KEY in the server's environment — never as a tool argument, so the key stays out of the transcript.

share_diagram and open_in_app are the bridge out of chat: a diagram Claude generates becomes something you can refine, restyle, and embed — see below.

The four marked no open a browser or launch the desktop app. Over HTTP that would happen on the machine running the server rather than on yours, so they are not offered there — see Serving over HTTP.

Beyond the MCP server

The MCP server is one entry point into Diagrammo — a whole ecosystem built on the same DGMO markup. Generate in chat, refine in a real editor, embed anywhere:

• diagrammo.app — the desktop app. open_in_app drops an AI-generated diagram straight into it, with live preview, palettes, and export.
• online.diagrammo.app — a full editor in the browser, zero install. share_diagram URLs open right here.
• Docs integrations — drop DGMO fenced code blocks into your docs site: remark-dgmo, astro-dgmo, docusaurus-plugin-dgmo, fumadocs-dgmo.
• Obsidian — the Diagrammo Diagrams community plugin renders DGMO in your vault.
• CLI — npx @diagrammo/dgmo-cli file.dgmo -o out.png, or install it with npm install -g @diagrammo/dgmo-cli (macOS and Linux).

One markup, everywhere. A diagram you generate here renders identically in the app, in your docs, and in Obsidian — because they all speak DGMO.

→ Try it free at diagrammo.app

Setup

Easiest — one command

Install the dgmo CLI and let it wire everything up:

npm install -g @diagrammo/dgmo-cli   # macOS and Linux
dgmo install                         # auto-detects Claude Code, Codex, Claude Desktop, Cursor, …

Prefer Homebrew or pacman? See diagrammo.app/dev.

dgmo install configures each detected assistant non-interactively and points it at dgmo mcp, so there's no separate package to install or prompts to answer. Target one surface with dgmo install claude-code (or codex, claude-desktop, …).

Manual configuration

Prefer to edit configs yourself? Point any MCP client at the server via npx (no global install needed):

This is the beginning of the README. Read the rest at the original. Read the full README ↗