Liturgical Calendar Skill

OnlineCredit Usage:1 per callTool:LiturgicalCalendarSkill

The tool

Give your agent the Catholic liturgical calendar. Call it as an MCP tool to fetch feast days, seasons and liturgical colors for any month.

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

Tool call

{
  "name": "LiturgicalCalendarSkill",
  "arguments": {}
}

Connecting

One server URL covers every skill 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.

Client config

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

Endpoint

https://api.vervekit.com/v1/mcp

Per-client setup — Claude Desktop, 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.

Argument	Type	Example	Description
`month`	integer	`2`	The month to get Liturgical Calendar data for (default: current month)
`year`Premium	integer	`2025`	The year to get Liturgical Calendar data for (default: current year)

What the model gets back

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

Result

{
  "status": "ok",
  "error": null,
  "data": {
    "2026-01-01": [
      {
        "id": "mary_mother_of_god",
        "precedence": "GENERAL_SOLEMNITY_3",
        "rank": "SOLEMNITY",
        "isHolyDayOfObligation": true,
        "isOptional": false,
        "colors": [
          "WHITE"
        ]
      }
    ],
    "2026-01-02": [
      {
        "id": "basil_the_great_and_gregory_nazianzen_bishops",
        "precedence": "GENERAL_MEMORIAL_10",
        "rank": "MEMORIAL",
        "isHolyDayOfObligation": false,
        "isOptional": false,
        "colors": [
          "WHITE"
        ],
        "weekday": {
          "id": "christmas_time_january_2",
          "date": "2026-01-02",
          "dateDef": {
            "dateFn": "weekdayBeforeEpiphany",
            "dateArgs": [
              2
            ],
            "yearOffset": 0
          },
          "dateExceptions": [],
          "alternativeTransferDateDefs": [],
          "precedence": "WEEKDAY_13",
          "rank": "WEEKDAY",
          "allowSimilarRankItems": false,
          "isHolyDayOfObligation": false,
          "isOptional": false,
          "i18nDef": [
            "seasons:christmas_time.before_epiphany",
            {
              "day": 2
            }
          ],
          "seasons": [
            "CHRISTMAS_TIME"
          ],
          "periods": [
            "DAYS_BEFORE_EPIPHANY",
            "CHRISTMAS_TO_PRESENTATION_OF_THE_LORD"
          ],
          "colors": [
            "WHITE"
          ],
          "commonsDef": [],

Fields

Fields marked Premium need a paid plan. On a plan without them the key is absent rather than wrong, so a model never reasons over a substituted value.

Field	Type	Example	Description
`2026-01-01`	array[1]	`list of rows`
`2026-01-01.0.id`	string	`mary_mother_of_god`	Unique identifier for the liturgical event
`2026-01-01.0.precedence`Premium	string	`GENERAL_SOLEMNITY_3`	Liturgical rank precedence level for the event
`2026-01-01.0.rank`	string	`SOLEMNITY`	Liturgical rank classification (e.g., WEEKDAY, FEAST)
`2026-01-01.0.isHolyDayOfObligation`	boolean	`true`	Whether event is a holy day of obligation
`2026-01-01.0.isOptional`	boolean	`false`	Whether the event is optional to observe
`2026-01-01.0.colors`	array	`["WHITE"]`	Liturgical colors for the event (e.g., PURPLE, WHITE)
`2026-01-02`	array[1]	`list of rows`
`2026-01-02.0.id`	string	`basil_the_great_and_gregory_nazianzen_bishops`	Unique identifier for the liturgical event
`2026-01-02.0.precedence`Premium	string	`GENERAL_MEMORIAL_10`	Liturgical rank precedence level for the event
`2026-01-02.0.rank`	string	`MEMORIAL`	Liturgical rank classification (e.g., WEEKDAY, FEAST)
`2026-01-02.0.isHolyDayOfObligation`	boolean	`false`	Whether event is a holy day of obligation
`2026-01-02.0.isOptional`	boolean	`false`	Whether the event is optional to observe
`2026-01-02.0.colors`	array	`["WHITE"]`	Liturgical colors for the event (e.g., PURPLE, WHITE)
`2026-01-02.0.weekday`	object	`{…}`
`2026-01-02.0.weekday.id`	string	`christmas_time_january_2`	Unique identifier for the liturgical event
`2026-01-02.0.weekday.date`	string	`2026-01-02`	ISO date string for the liturgical event
`2026-01-02.0.weekday.dateDef`	object	`{…}`
`2026-01-02.0.weekday.dateDef.dateFn`	string	`weekdayBeforeEpiphany`
`2026-01-02.0.weekday.dateDef.dateArgs`	array	`[2]`
`2026-01-02.0.weekday.dateDef.yearOffset`	number	`0`
`2026-01-02.0.weekday.dateExceptions`	array	`[]`
`2026-01-02.0.weekday.alternativeTransferDateDefs`	array	`[]`
`2026-01-02.0.weekday.precedence`Premium	string	`WEEKDAY_13`	Liturgical rank precedence level for the event
`2026-01-02.0.weekday.rank`	string	`WEEKDAY`	Liturgical rank classification (e.g., WEEKDAY, FEAST)
`2026-01-02.0.weekday.allowSimilarRankItems`	boolean	`false`	Whether similar rank items allowed on same date
`2026-01-02.0.weekday.isHolyDayOfObligation`	boolean	`false`	Whether event is a holy day of obligation
`2026-01-02.0.weekday.isOptional`	boolean	`false`	Whether the event is optional to observe
`2026-01-02.0.weekday.i18nDef`Premium	array	`["seasons:christmas_time.before_epiphany",{"day":2}]`	Internationalization definition for event naming
`2026-01-02.0.weekday.seasons`	array	`["CHRISTMAS_TIME"]`	Array of liturgical seasons (e.g., ADVENT, LENT)
`2026-01-02.0.weekday.periods`	array	`["DAYS_BEFORE_EPIPHANY","CHRISTMAS_TO_PRESENTATION_OF_THE_LORD"]`
`2026-01-02.0.weekday.colors`	array	`["WHITE"]`	Liturgical colors for the event (e.g., PURPLE, WHITE)
`2026-01-02.0.weekday.commonsDef`	array	`[]`
`2026-01-02.0.weekday.martyrology`	array	`[]`
`2026-01-02.0.weekday.titles`	array	`[]`
`2026-01-02.0.weekday.calendar`	object	`{…}`
`2026-01-02.0.weekday.calendar.weekOfSeason`	number	`2`
`2026-01-02.0.weekday.calendar.dayOfSeason`	number	`9`
`2026-01-02.0.weekday.calendar.dayOfWeek`	number	`5`
`2026-01-02.0.weekday.calendar.nthDayOfWeekInMonth`	number	`1`
`2026-01-02.0.weekday.calendar.startOfSeason`	string	`2025-12-25`
`2026-01-02.0.weekday.calendar.endOfSeason`	string	`2026-01-11`
`2026-01-02.0.weekday.calendar.startOfLiturgicalYear`	string	`2025-11-30`
`2026-01-02.0.weekday.calendar.endOfLiturgicalYear`	string	`2026-11-28`
`2026-01-02.0.weekday.calendar.seasons`	array	`["CHRISTMAS_TIME"]`	Array of liturgical seasons (e.g., ADVENT, LENT)
`2026-01-02.0.weekday.cycles`	object	`{…}`
`2026-01-02.0.weekday.cycles.properCycle`	string	`PROPER_OF_TIME`
`2026-01-02.0.weekday.cycles.sundayCycle`	string	`YEAR_A`
`2026-01-02.0.weekday.cycles.weekdayCycle`	string	`YEAR_2`
`2026-01-02.0.weekday.cycles.psalterWeek`	string	`WEEK_1`
`2026-01-02.0.weekday.fromCalendarId`Premium	string	`ProperOfTime`	Source calendar identifier for the event
`2026-01-02.0.weekday.fromExtendedCalendars`	array	`[]`
`2026-01-03`	array[2]	`list of rows`
`2026-01-03.0.id`	string	`christmas_time_january_3`	Unique identifier for the liturgical event
`2026-01-03.0.precedence`Premium	string	`WEEKDAY_13`	Liturgical rank precedence level for the event
`2026-01-03.0.rank`	string	`WEEKDAY`	Liturgical rank classification (e.g., WEEKDAY, FEAST)
`2026-01-03.0.isHolyDayOfObligation`	boolean	`false`	Whether event is a holy day of obligation
`2026-01-03.0.isOptional`	boolean	`false`	Whether the event is optional to observe
`2026-01-03.0.colors`	array	`["WHITE"]`	Liturgical colors for the event (e.g., PURPLE, WHITE)
`2026-01-04`	array[1]	`list of rows`

Failure modes

Errors come back as tool errors with a sentence the model can act on, not a bare status code.

Status	What it means
`400 / 422`	The arguments didn't validate. The message names the offending one.
`401`	The OAuth session is invalid or expired — reconnect the server.
`403`	Out of credits. Not a bad key — the month's allowance is spent.
`404`	This skill isn't part of VerveKit. Check the catalog.
`429`	Brief rate limit. Retrying after a moment succeeds.

Other ways to use Liturgical Calendar Skill

Set up Liturgical Calendar Skill on VerveKit, or reach the same source a different way. Your VerveKit 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 →

Use it in Google Sheets or ExcelA =VERVE() formula fills a column — no script, no export, recalculates in place.VerveSheets →Reference →

Ground an agent on itA cited, machine-checkable fact your model can't produce on its own.VerveContext →Reference →

Frequently asked questions

Do I have to tell the agent to use LiturgicalCalendarSkill?

No. The tool's name and description are in the model's context once the server is connected, so it selects the tool when the question calls for it. Naming it explicitly works too and is useful when you want to force the call.

Does connecting the server expose every tool at once?

Yes — one connection lists the whole VerveKit catalog. Clients with a tool budget can usually filter the list; the credit cost is per call, so an unused tool costs nothing.

What does a call cost?

1 credit each time the tool actually runs. A model that reasons about the tool without calling it costs nothing.

Is there a REST version of this?

Yes — the same source is available as a plain HTTPS endpoint on APIVerve, linked above. Same data, same credits, same account.

What's Next?

Continue your journey with these recommended resources

Browse all skills

The full catalog for this door

Connect a client

Claude, Cursor, VS Code and the rest

Plans & credits

What a call costs and how usage resets

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