uml.singsk.com PlantUML
Render, validate, encode/decode PlantUML diagram-as-code; 22 diagram types. Free, no auth.
Should I use this
Quality & Safety
Based on automated analysis of tool definitions and protocol compliance.
Context Cost
This is the approximate number of tokens consumed each time the server's tools are loaded into a model's context. Higher counts reduce the attention available for other tasks.
Install
One-Click Install
Add this to your `claude_desktop_config.json` file:
{
"mcpServers": {
"uml-plantuml": {
"url": "https://uml.singsk.com/mcp"
}
}
}Remote endpoints
https://uml.singsk.com/mcpstreamable-httpWhat it can do
Tool inventory
Tools (6)
⚪render_diagram(text, format)
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.
Input Schema
{
"type": "object",
"properties": {
"text": {
"type": "string",
"description": "PlantUML source including @startuml ... @enduml (or the matching @start/@end pair)"
},
"format": {
"type": "string",
"enum": [
"svg",
"png"
],
"default": "svg"
}
},
"required": [
"text"
]
}🟢validate_diagram(text)
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.
Input Schema
{
"type": "object",
"properties": {
"text": {
"type": "string"
}
},
"required": [
"text"
]
}🟡encode_source(text)
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.
Input Schema
{
"type": "object",
"properties": {
"text": {
"type": "string"
}
},
"required": [
"text"
]
}⚪decode_token(encoded)
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.
Input Schema
{
"type": "object",
"properties": {
"encoded": {
"type": "string",
"description": "Token or full render URL"
}
},
"required": [
"encoded"
]
}🟢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.
Input Schema
{
"type": "object",
"properties": {}
}🟢get_syntax_reference(type)
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.
Input Schema
{
"type": "object",
"properties": {
"type": {
"type": "string",
"description": "Type id or label, e.g. \"sequence\", \"class\", \"mindmap\", \"gantt\", \"json\""
}
},
"required": [
"type"
]
}Community
Evidence