API & MCP

Everything a person can do on Skyfold Planet Conjunctions and Best Evenings, a program or AI agent can do with the same inputs and get the identical result.

HTTP API

POST https://skyfoldconjunctions.usefulweb.app/api/v1/calculate – run Skyfold Planet Conjunctions and Best Evenings
GET https://skyfoldconjunctions.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.

Skyfold Planet Conjunctions and Best Evenings

Finds every close approach of the Moon, Mercury, Venus, Mars, Jupiter and Saturn, the oppositions of Mars to Neptune and the greatest elongations of Mercury and Venus, checks whether you can see them in the evening or morning twilight at your place and exports them as an .ics calendar.

Inputs of Skyfold Planet Conjunctions and Best Evenings
Field	Type	Default	Description
`location`	text	"52.0907, 5.1214"	Location (latitude, longitude). Decimal degrees such as 52.09, 5.12 (north and east positive), or DMS, UTM, MGRS, Maidenhead or a plus code.
`elevation`	number	0	Elevation above sea level
`timeZone`	text	"Europe/Amsterdam"	Time zone. IANA name such as Europe/Berlin or America/New_York, or a fixed offset such as UTC+2.
`startDate`	date	"2027-01-01"	From
`months`	integer	12	Months
`planetLimit`	number	3	Closest planet pairs within
`moonLimit`	number	3	Moon and planet within
`includeMoon`	boolean	true	Include the Moon
`visibleOnly`	boolean	true	Only events visible from this place

Example request

Utrecht, 2026

curl -X POST https://skyfoldconjunctions.usefulweb.app/api/v1/calculate -H 'content-type: application/json' -d '{"location":"52.0907, 5.1214","timeZone":"Europe/Amsterdam","startDate":"2026-01-01","months":12,"planetLimit":3,"moonLimit":3,"includeMoon":true,"visibleOnly":true}'

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://skyfoldconjunctions.usefulweb.app/mcp – protocol revisions 2026-07-28 (stateless) and 2025-11-25 / 2025-06-18 / 2025-03-26 (initialize handshake).
Tools: skyfold_conjunctions
Local stdio connector: node src/mcp-stdio.ts --tool=skyfold-conjunctions

{
  "mcpServers": {
    "skyfold-conjunctions": { "type": "http", "url": "https://skyfoldconjunctions.usefulweb.app/mcp" }
  }
}