API & MCP

Everything a person can do on Focus Room Big Sign, a program or AI agent can do with the same inputs and get the identical result.

HTTP API

POST https://focusroombigsign.usefulweb.app/api/v1/calculate – run Focus Room Big Sign
GET https://focusroombigsign.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.

Focus Room Big Sign

Fits your text — a word, a sentence or a few lines — into a full-screen sign: the largest font size at which it still fits with a margin, measured with the real Noto font metrics (Latin, Cyrillic, Greek, Arabic, Devanagari and common Chinese, Japanese and Korean characters). You get an SVG with the letters as outlines, a PNG for a TV, tablet or video call, an A4 landscape PDF to print and a link that opens the sign full screen in Focus Room, where it can also scroll as a marquee.

Inputs of Focus Room Big Sign
Field	Type	Default	Description
`text`	textarea	"Back in 10 minutes"	Text. Line breaks are kept; long lines are wrapped at spaces. At most 280 characters.
`theme`	select (night, paper, signal, alert, go, ocean, violet)	"night"	Colours
`size`	select (1920x1080, 1280x720, 1080x1920, 1080x1080)	"1280x720"	Picture size
`marquee`	boolean	false	Scroll as a marquee in the app. Only the app link scrolls; the files show the fitted sign.

Example request

“Back in 10 minutes” on signal yellow

curl -X POST https://focusroombigsign.usefulweb.app/api/v1/calculate -H 'content-type: application/json' -d '{"text":"Back in 10 minutes","theme":"signal","size":"1280x720"}'

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://focusroombigsign.usefulweb.app/mcp – protocol revisions 2026-07-28 (stateless) and 2025-11-25 / 2025-06-18 / 2025-03-26 (initialize handshake).
Tools: focusroom_big_sign
Local stdio connector: node src/mcp-stdio.ts --tool=focusroom-big-sign

{
  "mcpServers": {
    "focusroom-big-sign": { "type": "http", "url": "https://focusroombigsign.usefulweb.app/mcp" }
  }
}