UML-MCP

UML-MCP gives an AI assistant a real diagram tool instead of asking it to fake diagrams in Markdown. Connect it once over MCP, then ask for a class diagram, sequence diagram, architecture view, Mermaid flowchart, D2 graph, BPMN process, or another Kroki-backed format. The server validates the source, renders it, and returns a URL, playground link, or inline image.

It also works as a building block for agent-facing products. Use MCP when an agent needs diagram tools, AG-UI when a frontend needs a standard event stream, and OpenUI when the product should turn model output into interactive, application-owned UI components. These layers complement each other; UML-MCP stays focused on diagram generation.

Quick start

Remote (recommended) — add to your MCP client:

"uml-mcp": {
  "transport": "http",
  "url": "https://uml-mcp.vercel.app/mcp"
}

Use /mcp, not the site root. Then ask: “Draw a sequence diagram of a user logging in through an API gateway.” or paste PlantUML / Mermaid / Kroki source.

Repo defaults: .cursor/mcp.json · .vscode/mcp.json · .codex/config.toml.

All snippets: config/README.md

Install locally (guided):

Guide: docs/installation.md

git clone https://github.com/antoinebou12/uml-mcp.git
cd uml-mcp
uv sync
uv run python server.py

If you already have the repo and need to set origin:

git remote add origin https://github.com/antoinebou12/uml-mcp.git

Configs: config/README.md (Cursor, VS Code, Codex, Claude, Open WebUI, Continue)

/plugin marketplace add https://github.com/antoinebou12/uml-mcp
/plugin install uml-mcp@uml-mcp-plugins

docs/integrations/claude_code.md · Cursor skill: .skill/skills/uml-mcp-diagrams/SKILL.md

At a glance

Smoke prompts: tests/prompts/chatgpt_mcp_smoke_test.md

docs/diagrams/index.md

Vercel — connect the repo; clients use https://<project>.vercel.app/mcp.

Smithery — paste that /mcp URL at smithery.ai/new. Guide: docs/integrations/vercel_smithery.md.

Docker

docker compose up -d
docker build -t uml-mcp . && docker run -p 8000:8000 uml-mcp
docker run -i uml-mcp python server.py --transport stdio
# self-hosted PlantUML + mermaid.ink fallbacks next to local Kroki
MCP_DIAGRAM_FALLBACK=true USE_LOCAL_PLANTUML=true USE_LOCAL_MERMAID_INK=true docker compose --profile fallback up -d

docs/deploy/docker.md

Kubernetes + SSO: helm upgrade --install uml-mcp deploy/helm/uml-mcp --set auth.mode=jwt … (Entra ID or any OIDC provider); add --set kroki.enabled=true --set plantuml.enabled=true --set mermaidInk.enabled=true to run the renderers in-cluster. Guide: docs/enterprise.

Full list: docs/configuration.md · single file: docs/configuration/uml-mcp-yaml.md

Assistant → generate_uml / generate_uml_image → Kroki (+ fallbacks) → url, playground, optional image bytes.

server.py / app.py     -- MCP + FastAPI (/mcp)
mcp_core/tools/        -- generate_uml, generate_uml_image, validate, batch
tools/kroki/           -- Kroki, PlantUML, Mermaid, D2

Agent UI: canonical POST /ag-ui for AG-UI clients; legacy direct render at POST /ag-ui/generate. See frontend integration and OpenUI + UML-MCP.

uv sync --all-groups
uv run pytest tests/ -v
uv run ruff check . && uv run ruff format --check .
make ci

Docs locally: uv run mkdocs serve → http://127.0.0.1:8000

Optional and off by default (MCP_AUTH_MODE=none; the public Vercel endpoint stays open).

Community

If this survives a real production repo, it beats a lot of polished launch demos.

— @AIDailyGems on antoinebou12/uml-mcp

Daily and monthly activity (stars, forks, merged PRs, issues): trendshift.io/repositories/42725

Links

Maintained by Antoine Boucher. Built on PlantUML, Kroki, Mermaid, and D2.