API & MCP

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

HTTP API

POST https://greenplotcompanioncheck.usefulweb.site/api/v1/calculate – run Companion Planting Checker
GET https://greenplotcompanioncheck.usefulweb.site/api/v1/tool – inputs, output schema, examples
OpenAPI 3.1: /openapi.json · /openapi.yaml
Errors: application/problem+json; 422 includes per-field errors.

Companion Planting Checker

Checks every pair in a list of up to 40 vegetables, herbs, fruit and flowers for companions and antagonists. Each pair says why — a plain reason such as shared blight or shade, or gardening tradition with weak evidence — and same-family neighbours that share soil pests are listed too.

Inputs of Companion Planting Checker
Field	Type	Default	Description
`plants`	multiselect (tomato, pepper, eggplant, potato, cucumber, zucchini, squash, melon, sweetcorn, bush-bean, pole-bean, pea, broad-bean, lettuce, spinach, chard, beet, carrot, parsnip, radish, turnip, onio	["tomato","basil","potato","carrot","onion","bush-bean"]	Plants

Example request

Tomato bed with potatoes nearby

curl -X POST https://greenplotcompanioncheck.usefulweb.site/api/v1/calculate -H 'content-type: application/json' -d '{"plants":["tomato","basil","potato","carrot","onion","bush-bean"]}'

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://greenplotcompanioncheck.usefulweb.site/mcp – protocol revisions 2026-07-28 (stateless) and 2025-11-25 / 2025-06-18 / 2025-03-26 (initialize handshake).
Tools: greenplot_companion_check
Local stdio connector: node src/mcp-stdio.ts --tool=greenplot-companion-check

{
  "mcpServers": {
    "greenplot-companion-check": { "type": "http", "url": "https://greenplotcompanioncheck.usefulweb.site/mcp" }
  }
}