HTTP status: activities calendar validation

This page documents the problem type URI returned when GET /api/v1/activities/activities/calendar/ rejects the query string (missing window, unparseable datetimes, or ends_at not after starts_at).

Clients should branch on status, type, and structured errors[].code values (not only free-text detail).

Canonical problem type

type: "https://docs.keja.co/troubleshooting/status-codes/activities.calendar_validation"

HTTP mapping

Item	Value
Status code	422
Content-Type	application/problem+json
title (problem)	Short human label such as "Calendar requires a datetime window" or "Invalid calendar window".
detail (problem)	Human explanation; do not parse for automation.

Typical issue codes (errors[].code)

activities.calendar.missing_window

One or both of starts_at and ends_at were not provided.

activities.calendar.invalid_datetime

A parameter was present but not a valid ISO 8601 datetime.

activities.calendar.invalid_window

ends_at is not strictly after starts_at

Each issue object should include a pointer (for example "/query") where the API supplies it.