API & MCP

Everything a person can do on Sketchboard Mermaid to Diagram, a program or AI agent can do with the same inputs and get the identical result.

HTTP API

POST https://sketchboardmermaidtodiagram.usefulweb.app/api/v1/calculate – run Sketchboard Mermaid to Diagram
GET https://sketchboardmermaidtodiagram.usefulweb.app/api/v1/tool – inputs, output schema, examples
OpenAPI 3.1: /openapi.json · /openapi.yaml
Errors: application/problem+json; 422 includes per-field errors.

Sketchboard Mermaid to Diagram

Parses the flowchart part of Mermaid (directions, node shapes, labelled and dotted links, chains, subgraphs), places the nodes with a layered layout so few lines cross, routes the connectors around the boxes and returns an SVG plus a Sketchboard board where every box and arrow can be moved and restyled.

Inputs of Sketchboard Mermaid to Diagram
Field	Type	Default	Description
`mermaid`	textarea	—	Mermaid flowchart. Starts with “flowchart TD” (or graph LR …). One link per line, for example A[Start] --> B{OK?}.
`direction`	select (, TB, LR, BT, RL)	—	Direction
`route`	select (elbow, straight, curved)	"elbow"	Connector style
`style`	select (clean, sketchy, file)	"clean"	Drawing style

Example request

Sign-up flow with decisions

curl -X POST https://sketchboardmermaidtodiagram.usefulweb.app/api/v1/calculate -H 'content-type: application/json' -d '{"mermaid":"flowchart TD\n  start([Visitor opens the sign-up page]) --> form[Fill in name and e-mail]\n  form --> valid{Is the e-mail valid?}\n  valid -- no --> err[Show a clear error message] --> form\n  valid -- yes --> exists{Account exists already?}\n  exists -- yes --> login[Offer to sign in instead]\n  exists -- no --> create[(Create the account)]\n  create --> mail[Send the welcome e-mail]\n  mail --> done([Show the dashboard])\n  login --> done"}'

Every result contains

inputs (normalised, defaults applied), summary, result (validated against the published schema), units, assumptions, sources, warnings, computedAt and links.

MCP (Model Context Protocol)

Streamable HTTP endpoint: https://sketchboardmermaidtodiagram.usefulweb.app/mcp – protocol revisions 2026-07-28 (stateless) and 2025-11-25 / 2025-06-18 / 2025-03-26 (initialize handshake).
Tools: sketchboard_mermaid_to_diagram
Local stdio connector: node src/mcp-stdio.ts --tool=sketchboard-mermaid-to-diagram

{
  "mcpServers": {
    "sketchboard-mermaid-to-diagram": { "type": "http", "url": "https://sketchboardmermaidtodiagram.usefulweb.app/mcp" }
  }
}