umple-diagram-generator

name

umple-diagram-generator

description

Generate diagrams (state machines, class diagrams, ER diagrams) from natural language requirements using Umple. Use when user requests: (1) State machine diagrams (2) UML class diagrams (3) ER diagrams, entity-relationship diagrams, or database schema diagrams (4) Diagram generation from text descriptions, (5) Any mention of Umple diagram generation, (6) Visual representation of states, transitions, events, entities, classes, or relationships. Outputs SVG diagrams with organized folder structure.

Umple Diagram Generator

Supported diagram types

Type	language value	Read first
Class diagram	classDiagram	references/class-diagram-syntax.md
State machine	stateDiagram	references/state-machine-syntax.md
ER diagram	entityRelationshipDiagram	references/class-diagram-syntax.md
Trait diagram	traitDiagram	references/class-diagram-syntax.md

Workflow

1. Read the syntax reference for the requested diagram type.
2. Write valid Umple code.
3. Call the Umple Online API (see below).
4. Extract SVG from the response and save to a .svg file.
5. On error, read the message, fix the code, retry (up to 3 times).
6. Render the SVG inline for the user.

API

Endpoint: POST https://cruise.umple.org/umpleonline/scripts/compiler.php Content-Type: application/x-www-form-urlencoded

Parameter	Value
language	See table above
languageStyle	diagramUpdate
umpleCode	The Umple source code
filename	model.ump

Use whatever HTTP tool is available (WebFetch, curl, fetch, etc.).

Response parsing

Success: response contains two nested <svg> tags. Extract the inner SVG — the one with a viewBox attribute. Clean up any xlink:href="javascript:..." attributes.

Error: response contains <span class="umple-message-error">. Strip HTML tags to read the error.

Output

1. State the diagram type.
2. Show the Umple source in an umple code block.
3. Render the SVG visually.
4. Save files: <name>/model.ump and <name>/diagram.svg.

Guardrails

• Always read the syntax reference before writing Umple code.
• Prefer a smaller valid model over guessing syntax.
• One association per class pair — never define the same relationship from both sides.
• Never use Final as a custom state name — it is a reserved keyword in Umple. Use Done, Completed, etc. instead.