Docs/Sources/Mayan Calendar Grounding Data

Mayan Calendar Grounding Data

Convert Gregorian to Mayan Calendar

OperationalCredits 2 per callp50 219msReference Data

Overview

Uses the GMT (Goodman-Martinez-Thompson) correlation constant for accurate conversion. Ideal for educational content, historical research, and cultural applications.

Live Test Mayan Calendar Grounding Data Source →

The tool

Once your client is connected to the VerveContext server, this appears in its tool list as MayanCalendarGroundingData. It is read-only and open-world — it fetches and never mutates anything on your side — so most clients call it without asking you to confirm.

Tool call
{
  "name": "MayanCalendarGroundingData",
  "arguments": {
    "date": "2024-12-21"
  }
}

You do not name the tool yourself; the model picks it. Asking about 2024-12-21 in the terms this source covers is enough for it to reach for MayanCalendarGroundingData on its own — naming it explicitly also works, and is the way to force the call.

Connecting

One server URL covers every source in the catalog, including this one. Authorization is OAuth: the client opens a browser once, and there is no key to paste into a config file.

{
  "mcpServers": {
    "vervecontext": {
      "url": "https://api.vervecontext.com/v1/mcp"
    }
  }
}

Per-client setup — Claude, Cursor, VS Code, ChatGPT — is on the MCP setup page.

Arguments

These are the properties on the tool's inputSchema, so a well-behaved client validates them before the call is made. Premium arguments are accepted on every plan but only take effect on plans that include them.

ArgumentTypeDescription
dateRequiredstringThe Gregorian date in YYYY-MM-DD format
date

What the model gets back

The result carries a structuredContent object matching the tool's declared outputSchema, so a client reads fields without parsing prose. status is "ok" and error is null on success; a null field means the value was not available for that input, not that the call failed.

Result
{
  "status": "ok",
  "error": null,
  "data": {
    "gregorian": "2024-12-21",
    "longCount": {
      "formatted": "13.0.12.3.3",
      "baktun": 13,
      "katun": 0,
      "tun": 12,
      "winal": 3,
      "kin": 3
    },
    "tzolkin": {
      "number": 6,
      "dayName": "Akbal",
      "formatted": "6 Akbal"
    },
    "haab": {
      "day": 6,
      "monthName": "Kankin",
      "formatted": "6 Kankin"
    },
    "calendarRound": "6 Akbal 6 Kankin",
    "daysSinceEpoch": 1876383
  }
}

Response fields

Paths are relative to data. Premium fields are absent rather than zeroed on plans that do not include them, so check for presence instead of comparing to 0.

FieldTypeExampleDescription
gregorianstring2024-12-21The input Gregorian date in YYYY-MM-DD format
longCountobject{…}
longCount.formattedstring13.0.12.3.3Mayan Long Count formatted as baktun.katun.tun.winal.kin
longCount.baktunPremiumnumber13Long Count baktun component (cycle of 400 tuns)
longCount.katunPremiumnumber0Long Count katun component (cycle of 20 tuns)
longCount.tunPremiumnumber12Long Count tun component (cycle of 18 winals)
longCount.winalPremiumnumber3Long Count winal component (cycle of 20 kins)
longCount.kinPremiumnumber3Long Count kin component (day unit in Mayan calendar)
tzolkinobject{…}
tzolkin.numberPremiumnumber6Tzolkin sacred calendar day number (1-13)
tzolkin.dayNamePremiumstringAkbalTzolkin day name from 20-day Mayan sacred cycle
tzolkin.formattedstring6 AkbalTzolkin date formatted as number and day name
haabobject{…}
haab.dayPremiumnumber6Haab civil calendar day number (0-19 or 0-4)
haab.monthNamePremiumstringKankinHaab month name from 18-month Mayan civil calendar
haab.formattedstring6 KankinHaab date formatted as day and month name
calendarRoundPremiumstring6 Akbal 6 KankinCalendar Round combining Tzolkin and Haab dates
daysSinceEpochPremiumnumber1876383Days since Mayan creation date (0.0.0.0.0)

Why ground on it

A model can produce something that looks like this answer from its training data, and be confidently out of date or simply wrong. This source returns the current value in a shape you can check, which is the difference between an answer you can cite and one you have to hedge.

Point an evaluation at gregorian: it is the field most worth pinning a claim to, and it is either present and current or absent — never plausibly invented.

Failure modes

Errors come back as tool errors carrying a sentence the model can act on, not a bare status code. Error handling covers the full list.

StatusWhat it means
400 / 422The arguments did not validate. The message names the offending one.
401The OAuth session is invalid or expired — reconnect the server.
403Blocked by a key restriction or an IP allow-list. Never a bad identity.
404This source is not part of VerveContext. Check the catalog.
429Out of credits, or a brief rate limit. The message tells them apart.

A call costs 2 credits each time the tool actually runs; a model that reasons about the tool without calling it costs nothing.

Use cases

Educational Tools
Teach about ancient Mesoamerican calendar systems
Cultural Applications
Display Mayan dates for heritage and cultural apps
Historical Research
Convert dates for archaeological and historical study
Novelty Apps
Generate personalized Mayan birth dates

Other ways to use Mayan Calendar Grounding Data

Set up Mayan Calendar Grounding Data on VerveContext, or reach the same source a different way. Your VerveContext account and credits work on all of them — one key, one balance.

Call it as a REST APIOne HTTPS endpoint and an x-api-key header, with SDKs for Node, Python and .NET.APIVerve →Reference →
Give it to an AI agentConnect over MCP and your agent calls it as a native tool — Claude, Cursor, ChatGPT.VerveKit →Reference →
Google Sheets or ExcelA =VERVE() formula fills a column — no script, no export, recalculates in place.VerveSheets →Reference →

More in Reference Data:

Was this page helpful?