API & MCP

Everything a person can do on Sizewise Life in Weeks, a program or AI agent can do with the same inputs and get the identical result.

HTTP API

POST https://sizewiselifeweeks.usefulweb.app/api/v1/calculate – run Sizewise Life in Weeks
GET https://sizewiselifeweeks.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.

Sizewise Life in Weeks

Draws a life-in-weeks grid from a birth date — one row per year, 52 boxes per row — with the current week, your milestones and exact counts of days, weeks, Sundays and leap days lived. Nothing is stored.

Inputs of Sizewise Life in Weeks
Field	Type	Default	Description
`birthDate`	date	"1990-06-15"	Birth date
`today`	date	—	Count up to (empty = today)
`years`	integer	90	Years in the grid
`milestones`	textarea	—	Milestones (one per line: date, then a label). For example “2012-09-01 First job”.

Example request

Born 15 June 1990, on 8 November 2026

curl -X POST https://sizewiselifeweeks.usefulweb.app/api/v1/calculate -H 'content-type: application/json' -d '{"birthDate":"1990-06-15","today":"2026-11-08","years":90,"milestones":"1996-09-02 First day at school\n2008-07-01 First job"}'

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://sizewiselifeweeks.usefulweb.app/mcp – protocol revisions 2026-07-28 (stateless) and 2025-11-25 / 2025-06-18 / 2025-03-26 (initialize handshake).
Tools: sizewise_life_weeks
Local stdio connector: node src/mcp-stdio.ts --tool=sizewise-life-weeks

{
  "mcpServers": {
    "sizewise-life-weeks": { "type": "http", "url": "https://sizewiselifeweeks.usefulweb.app/mcp" }
  }
}