Web-page view of https://agent.index.cy/api/listing-fields for tools that read pages and follow links. The text below is the complete answer; every address in it is a link you can open. Command-line tools get the raw form.

{
    "deal": "sale",
    "fields": {
        "deal": {
            "values": [
                "sale",
                "rent"
            ],
            "note": "Cannot be changed after the listing is created."
        },
        "property_type": {
            "values": [
                "apartment",
                "building",
                "house",
                "land-plots",
                "office",
                "commercial"
            ],
            "multiple": false,
            "note": "Common words are understood: villa, bungalow, townhouse and maisonette are filed as house; flat and penthouse as apartment; plot and land as land-plots."
        },
        "condition": {
            "values": [
                "brand-new",
                "pre-owned",
                "under-construction"
            ],
            "multiple": false
        },
        "bedrooms": {
            "values": [
                "studio",
                "1",
                "2",
                "3",
                "4",
                "5",
                "6"
            ],
            "multiple": false,
            "note": "A number or a string, both work."
        },
        "bathrooms": {
            "values": [
                "1",
                "2",
                "3",
                "4",
                "5"
            ],
            "multiple": false
        },
        "district": {
            "values": [
                "famagusta",
                "larnaca",
                "limassol",
                "nicosia",
                "paphos"
            ],
            "multiple": false
        },
        "location": {
            "values_from": "GET https://agent.index.cy/api/locations?q=<name> (use the slug)",
            "multiple": false
        },
        "year_built": {
            "values": [
                "1990-and-older",
                "1991-2000",
                "2001-2010",
                "2009",
                "2011",
                "2012",
                "2013",
                "2014",
                "2015",
                "2016",
                "2017",
                "2018",
                "2019",
                "2020",
                "2021",
                "2022",
                "2023",
                "2024",
                "2025",
                "2026",
                "2027",
                "2028",
                "2029",
                "2030"
            ],
            "multiple": false,
            "note": "Send the exact year (2008): index.cy files it under its own range (2001-2010)."
        },
        "energy_class": {
            "values": [
                "a",
                "a-plus",
                "b",
                "b-plus",
                "c",
                "d",
                "e"
            ],
            "multiple": false
        },
        "furnishing": {
            "values": [
                "furnished",
                "partially-furnished",
                "unfurnished"
            ],
            "multiple": false
        },
        "pool": {
            "values": [
                "common",
                "no",
                "private",
                "yes"
            ],
            "multiple": true
        },
        "parking": {
            "values": [
                "covered",
                "no",
                "uncovered",
                "yes"
            ],
            "multiple": true
        },
        "heating": {
            "values": [
                "autonomous-heating",
                "central-heating",
                "no",
                "radiators",
                "underfloor-heating",
                "yes"
            ],
            "multiple": true
        },
        "air_conditioning": {
            "values": [
                "all-rooms",
                "no",
                "partial",
                "yes"
            ],
            "multiple": true
        },
        "amenities": {
            "values": [
                "air-conditioning",
                "alarm",
                "balcony",
                "bbq-zone",
                "bike-parking",
                "elevator",
                "fireplace",
                "garden",
                "guest-wc",
                "gym",
                "heating",
                "parking",
                "pool",
                "roof-garden",
                "spasauna",
                "storage-room"
            ],
            "multiple": true,
            "note": "pool, parking, heating and air-conditioning here are separate from the fields of the same name. Set the field (it says which kind) AND the amenity (buyers filter on it) when the home has one."
        },
        "view": {
            "values": [
                "city-view",
                "mountains-view",
                "sea-view"
            ],
            "multiple": true
        },
        "price": {
            "type": "number",
            "min": 1,
            "max": 999999999
        },
        "covered_area_m2": {
            "type": "number",
            "min": 1,
            "max": 999999
        },
        "plot_area_m2": {
            "type": "number",
            "min": 1,
            "max": 99999999
        },
        "internal_area_m2": {
            "type": "number",
            "min": 1,
            "max": 999999
        },
        "covered_veranda_m2": {
            "type": "number",
            "min": 0,
            "max": 99999
        },
        "uncovered_veranda_m2": {
            "type": "number",
            "min": 0,
            "max": 99999
        },
        "floor": {
            "type": "number",
            "min": -3,
            "max": 200
        },
        "floors_in_building": {
            "type": "number",
            "min": 1,
            "max": 200
        },
        "postal_code": {
            "type": "number",
            "min": 1000,
            "max": 9999
        },
        "title_deed": {
            "values": [
                "has-title",
                "no-title"
            ]
        },
        "description": {
            "type": "text",
            "note": "Plain text, blank lines between paragraphs, up to 6000 characters. No phone numbers, emails or links: buyers reach the seller through the listing."
        },
        "reference": {
            "type": "text",
            "note": "The seller's own reference, up to 60 characters. It is the key for CRM sync."
        },
        "video_url": {
            "type": "text",
            "note": "A YouTube link."
        },
        "lat": {
            "type": "number",
            "note": "With lng. Must be in Cyprus."
        },
        "lng": {
            "type": "number"
        },
        "address": {
            "type": "text",
            "note": "Shown with the map pin. Optional."
        },
        "photo_urls": {
            "type": "list of https image URLs",
            "note": "JPEG, PNG or WebP, up to 30. Imported 5 per call: repeat the same request while photos.pending is above 0."
        }
    },
    "needed_to_publish": {
        "always": [
            "property_type",
            "district",
            "price",
            "photo_urls"
        ],
        "apartment, house": [
            "bedrooms",
            "covered_area_m2",
            "condition"
        ],
        "land-plots": [
            "plot_area_m2"
        ],
        "office, building, commercial": [
            "covered_area_m2"
        ]
    },
    "note": "photo_urls: at least one photo must have been imported. missing_to_publish on a listing uses these same names.",
    "set_by_index_cy": "title, link, price per m2, VAT or transfer fee, seller details: never send these.",
    "updates": "On PATCH and PUT, fields you leave out stay as they are; null clears one. photo_urls is always the complete photo list."
}