API & MCP

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

HTTP API

• GET https://greenplot.usefulweb.app/api/v1/tools – catalog
• GET https://greenplot.usefulweb.app/api/v1/tools/{id} – inputs, output schema, examples
• POST https://greenplot.usefulweb.app/api/v1/tools/{id}/calculate – run a tool
• GET https://greenplot.usefulweb.app/api/v1/workflows · POST https://greenplot.usefulweb.app/api/v1/workflows/{id}/run
• OpenAPI 3.1: /openapi.json · /openapi.yaml
• Errors: application/problem+json; 422 includes per-field errors.

Tools on Greenplot

• Garden Sowing Calendar (122 Plants) – Sowing, planting, harvest and pruning dates for 122 garden plants from your frost dates. greenplot_sowing_calendar
• Succession Sowing Planner – Space repeat sowings of lettuce, radish, beans and more so you harvest all season. greenplot_succession_planner
• Companion Planting Checker – Check which of your plants go well together, which to keep apart, and why. greenplot_companion_check
• Garden Weather Tasks – Frost warnings, watering you can skip after rain, and litres per bed from the MET Norway forecast. greenplot_weather_tasks
• Frost Dates Finder – Last spring and first autumn frost at your place, with the chance of a later or earlier frost. hearth_frost_dates

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://greenplot.usefulweb.app/mcp – protocol revisions 2026-07-28 (stateless) and 2025-11-25 / 2025-06-18 / 2025-03-26 (initialize handshake).
• Tools: greenplot_sowing_calendar, greenplot_succession_planner, greenplot_companion_check, greenplot_weather_tasks, hearth_frost_dates
• Local stdio connector: node src/mcp-stdio.ts

{
  "mcpServers": {
    "usefulweb": { "type": "http", "url": "https://greenplot.usefulweb.app/mcp" }
  }
}