{"id":"iso-date-month-start","version":"1.0.0","description":"Return the first calendar day of the year-month of a YYYY-MM-DD date.","supported_operations":["iso date month start","first day of month","start of calendar month"],"unsupported_operations":["ISO week start","fiscal year start","timezone local midnight","datetime truncate","last day of month","add months"],"semantics":["date is a proleptic Gregorian UTC calendar date YYYY-MM-DD with years 0001-9999.","Output is the same year and month with day 01.","No time zone, locale, or week-start adjustment is applied."],"limits":{"min_year":1,"max_year":9999},"pricing":{"status":"unpriced","charge_usd":null},"input_schema":{"type":"object","additionalProperties":false,"required":["date"],"properties":{"date":{"type":"string","pattern":"^\\d{4}-\\d{2}-\\d{2}$","maxLength":10}}},"output_schema":{"type":"object","additionalProperties":false,"required":["date"],"properties":{"date":{"type":"string","pattern":"^\\d{4}-\\d{2}-\\d{2}$","maxLength":10}}},"examples":[{"input":{"date":"2026-03-15"},"output":{"date":"2026-03-01"}}],"execute_url":"/v1/tools/iso-date-month-start/versions/1.0.0/execute"}