uml.singsk.com PlantUML MCP Server

by singsk Your server? Claim it

not responding

uml.singsk.com PlantUML is listed as active in the registry but did not answer our last check. It exposes 6 tools.

Render, validate, encode/decode PlantUML diagram-as-code; 22 diagram types. Free, no auth.

Uptime history 71 days of history · worst day 0%

71 days agonow

0.0%

Uptime 24h

0 of 91 checks

Tools

read from the server

8000 ms

Response time

average over 24h

open, no key

Access

streamable-http

uml.singsk.com PlantUML does not always answer

Over the last week it answered 31.4% of our checks. We check every 15 minutes, so you hear about the next outage within the hour — not from your users.

Connect this server

Endpoint below is the one we actually reach during checks — not the one copied from a README. Last verified 11 min ago.

Claude Code Claude Desktop Codex Cursor VS Code

run in your terminal

claude mcp add uml-plantuml --transport http https://uml.singsk.com/mcp

Settings → Connectors → Add custom connector, then paste this address

https://uml.singsk.com/mcp

~/.codex/config.toml

[mcp_servers.uml-plantuml]
url = "https://uml.singsk.com/mcp"

.cursor/mcp.json

{
  "mcpServers": {
    "uml-plantuml": {
      "url": "https://uml.singsk.com/mcp"
    }
  }
}

.vscode/mcp.json

{
  "servers": {
    "uml-plantuml": {
      "type": "http",
      "url": "https://uml.singsk.com/mcp"
    }
  }
}

Available tools 6

Read directly from the server with tools/list, grouped by what they act on. If a tool disappears, we record the date.

decode

decode_token

Recover the PlantUML source from a token or from any PlantUML render URL (the token is extracted automatically). Tokens use PlantUML's own 64-character alphabet ("0-9 A-Z a-z - _") over raw DEFLATE. This is NOT base64 - never encode or decode tokens with a base64 codec; use encode_source / decode_token.

diagram

list_diagram_types

List the 22 supported diagram/reference types with a one-line description and the local syntax reference URL for each. Use it to pick the right @start directive.

encode

encode_source

Encode PlantUML source into a URL token and ready-to-use share/render URLs (svg + png). The result carries url_ok: GET URLs only work while the token is at most 16000 characters; when url_ok is false do not share the URLs - render with render_diagram instead (it uses the POST API, no size limit up to 5 MB). Tokens use PlantUML's own 64-character alphabet ("0-9 A-Z a-z - _") over raw DEFLATE. This is NOT base64 - never encode or decode tokens with a base64 codec; use encode_source / decode_token.

render

render_diagram

Render PlantUML source text to a diagram image. Returns a PNG image block (format "png") or the SVG markup as text (format "svg", default), plus the shareable render URL. The source is validated first: on a syntax error the result is an error object with line, column, hint and a help link so you can fix the diagram and retry.

syntax

get_syntax_reference

Get the syntax reference entry for one diagram type: description, a render-verified example, and the help page URL. Use it to ground diagram generation.

validate

validate_diagram

Check PlantUML source without rendering. Returns {ok:true, diagram_type} or {ok:false, error:{code, message, line, column, source_line, hint, diagram_type_detected, help}}. Cheap - call it in a generate -> validate -> fix loop before rendering.

Endpoints

URL	Transport	State	Latency	Checked
https://uml.singsk.com/mcp	streamable-http	answering	8000 ms	11 min ago

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uml.singsk.com PlantUML — questions

Answers built from our own checks of this server.

What can uml.singsk.com PlantUML do?

It exposes 6 tools, read directly from the server on our last check. Among them: decode_token, encode_source, get_syntax_reference, list_diagram_types, render_diagram, validate_diagram. The full list with descriptions is on this page — we take it from the server itself via tools/list, not from a README. How MCP servers expose tools in the first place →

Is uml.singsk.com PlantUML working right now?

We send a real MCP handshake every 15 minutes. Over the last 24 hours 0 of 91 checks got a reply (0.0%), average response time 8000 ms. The bar chart above shows every period we have measured.

The registry lists uml.singsk.com PlantUML as active — why does it not respond?

The official MCP registry stores what the author submitted; it does not verify that the server still runs. We check the endpoint ourselves, and this one does not answer. Catalogues that copy the registry without checking will show it as working.

How do I connect uml.singsk.com PlantUML?

Copy the ready config from this page. We generate it for Claude Code, Claude Desktop, Codex, Cursor and VS Code, each in the form that client actually reads. It is a remote server, so there is nothing to install — the client connects to the address.

Does uml.singsk.com PlantUML need an API key?

No. uml.singsk.com PlantUML completed a full MCP handshake with us as an anonymous client and listed its tools without asking for anything. All 6 of them are readable on this page. This is what we observed, not what the docs claim.