API & MCP

Everything a person can do on Everyday Size Compare, a program or AI agent can do with the same inputs and get the identical result.

HTTP API

POST https://hearthsizecompare.usefulweb.app/api/v1/calculate – run Everyday Size Compare
GET https://hearthsizecompare.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.

Everyday Size Compare

Compare measured objects in front, side or top view, with unit conversion, a shared scale, overlays and relative dimensions.

Inputs of Everyday Size Compare
Field	Type	Default	Description
`objects`	table	[{"name":"Old monitor","width":540,"height":330,"depth":60},{"name":"New monitor	Objects
`view`	select (front, side, top)	"front"	View
`layout`	select (overlay, beside)	"overlay"	Layout
`unit`	select (mm, cm, in)	"mm"	Input unit

Example request

Try an example

curl -X POST https://hearthsizecompare.usefulweb.app/api/v1/calculate -H 'content-type: application/json' -d '{}'

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://hearthsizecompare.usefulweb.app/mcp – protocol revisions 2026-07-28 (stateless) and 2025-11-25 / 2025-06-18 / 2025-03-26 (initialize handshake).
Tools: hearth_size_compare
Local stdio connector: node src/mcp-stdio.ts --tool=hearth-size-compare

{
  "mcpServers": {
    "hearth-size-compare": { "type": "http", "url": "https://hearthsizecompare.usefulweb.app/mcp" }
  }
}