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Menstrual Cycle Prediction for AI AgentsMenstrual Cycle Prediction for AI Agents

OnlineCredit Usage:1 per callTool:MenstrualCyclePredictionforAIAgents

The tool

The API generates detailed cycle calendars with phase information including menstruation, follicular, ovulation, and luteal phases for multiple upcoming cycles.

Once your client is connected to the VerveContext MCP server, this appears in its tool list as MenstrualCyclePredictionforAIAgents. 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": "MenstrualCyclePredictionforAIAgents",
  "arguments": {
    "last_period": "2024-01-01"
  }
}

What that looks like in a conversation

You don't name the tool — the model picks it. Asking about 2024-01-01 in the terms this source covers is enough for it to reach for MenstrualCyclePredictionforAIAgents on its own.

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.

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

ArgumentTypeExampleDescription
last_periodRequiredstring2024-01-01First day of last menstrual period (YYYY-MM-DD)
cycle_lengthinteger28Average cycle length in days
period_lengthinteger5Average period duration in days
cyclesinteger3Number of future cycles to calculate

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": {
    "last_period_date": "2024-01-01",
    "cycle_length": 28,
    "period_length": 5,
    "cycles_calculated": 3,
    "cycles": [
      {
        "cycle_number": 1,
        "period": {
          "start_date": "2024-01-01",
          "end_date": "2024-01-05",
          "duration_days": 5
        },
        "ovulation": {
          "date": "2024-01-15",
          "day_of_cycle": 14
        },
        "fertile_window": {
          "start_date": "2024-01-10",
          "end_date": "2024-01-15",
          "duration_days": 6
        },
        "pms_phase": {
          "start_date": "2023-12-21",
          "end_date": "2023-12-31"
        },
        "cycle_phases": {
          "menstrual": {
            "start": "2024-01-01",
            "end": "2024-01-05",
            "description": "Menstruation"
          },
          "follicular": {
            "start": "2024-01-06",
            "end": "2024-01-14",
            "description": "Follicular phase - preparing for ovulation"
          },
          "ovulation": {
            "date": "2024-01-15",
            "description": "Ovulation - most fertile day"
          },
          "luteal": {
            "start": "2024-01-16",
            "end": "2024-01-28",
            "description": "Luteal phase - preparing for next period"
          }
        },
        "status": "past",
        "days_until": null,
        "days_ago": 715
      },
      {
        "cycle_number": 2,
        "period": {
          "start_date": "2024-01-29",
          "end_date": "2024-02-02",
          "duration_days": 5

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.
FieldTypeExampleDescription
last_period_datestring2024-01-01First day of last menstrual period
cycle_lengthnumber28Average menstrual cycle length in days
period_lengthnumber5Average menstrual period duration in days
cycles_calculatednumber3Total number of cycles calculated
cyclesarray[3]list of rowsArray of calculated menstrual cycles with details
└ cycles.0.cycle_numbernumber1Sequential number of the cycle
└ cycles.0.periodobject{…}Start, end and length of the period for this cycle
└ cycles.0.period.start_datestring2024-01-01Start date of menstrual period
└ cycles.0.period.end_datestring2024-01-05End date of menstrual period
└ cycles.0.period.duration_daysnumber5Duration of period in days
└ cycles.0.ovulationobject{…}Estimated ovulation date and which day of the cycle it falls on
└ cycles.0.ovulation.datestring2024-01-15Predicted ovulation date in cycle
└ cycles.0.ovulation.day_of_cyclenumber14Day of cycle when ovulation occurs
└ cycles.0.fertile_windowobject{…}Range of days conception is possible in this cycle
└ cycles.0.fertile_window.start_datestring2024-01-10Start of fertile window for conception
└ cycles.0.fertile_window.end_datestring2024-01-15End of fertile window for conception
└ cycles.0.fertile_window.duration_daysnumber6Duration of fertile window in days
└ cycles.0.pms_phaseobject{…}Range of days premenstrual symptoms are expected
└ cycles.0.pms_phase.start_datePremiumstring2023-12-21Start date of PMS phase
└ cycles.0.pms_phase.end_datePremiumstring2023-12-31End date of PMS phase
└ cycles.0.cycle_phasesPremiumobject{…}Detailed breakdown of menstrual cycle phases
└ cycles.0.cycle_phases.menstrualPremiumobject{…}The bleeding phase, with its dates
└ cycles.0.cycle_phases.menstrual.startPremiumstring2024-01-01Start date of menstrual phase
└ cycles.0.cycle_phases.menstrual.endPremiumstring2024-01-05End date of menstrual phase
└ cycles.0.cycle_phases.menstrual.descriptionPremiumstringMenstruationDescription of menstrual phase
└ cycles.0.cycle_phases.follicularPremiumobject{…}From the end of the period to ovulation
└ cycles.0.cycle_phases.follicular.startPremiumstring2024-01-06Start date of follicular phase
└ cycles.0.cycle_phases.follicular.endPremiumstring2024-01-14End date of follicular phase
└ cycles.0.cycle_phases.follicular.descriptionPremiumstringFollicular phase - preparing for ovulationDescription of follicular phase
└ cycles.0.cycle_phases.ovulationPremiumobject{…}The day the egg is released
└ cycles.0.cycle_phases.ovulation.datePremiumstring2024-01-15Ovulation date within cycle
└ cycles.0.cycle_phases.ovulation.descriptionPremiumstringOvulation - most fertile dayDescription of ovulation phase
└ cycles.0.cycle_phases.lutealPremiumobject{…}From ovulation to the start of the next period
└ cycles.0.cycle_phases.luteal.startPremiumstring2024-01-16Start date of luteal phase
└ cycles.0.cycle_phases.luteal.endPremiumstring2024-01-28End date of luteal phase
└ cycles.0.cycle_phases.luteal.descriptionPremiumstringLuteal phase - preparing for next periodDescription of luteal phase
└ cycles.0.statusPremiumstringpastStatus of cycle relative to current date
└ cycles.0.days_untilPremiumobjectnullDays until cycle phase occurs
└ cycles.0.days_agoPremiumnumber715Days since cycle phase occurred
current_statusobject{…}Which phase today falls in and when the next period is due
└ current_status.phasePremiumstringUnknownCurrent menstrual cycle phase name
└ current_status.descriptionPremiumstringDescription of current cycle phase
└ current_status.next_periodPremiumobjectnullDate of next expected menstrual period
└ current_status.days_until_next_periodPremiumobjectnullDays until next menstrual period starts
averagesobject{…}Average cycle length, period duration and gap between periods
└ averages.cycle_lengthPremiumnumber28Average menstrual cycle length across periods
└ averages.period_durationPremiumnumber5Average menstrual period duration across cycles
└ averages.days_between_periodsPremiumnumber28Average days between menstrual period starts
disclaimerstringThis calculator provides estimates only. Actual cycles may vary. Consult a healthcare provider for medical advice.Legal disclaimer about calculation accuracy

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 with 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 last_period_date: 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 with a sentence the model can act on, not a bare status code.

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

Other ways to use Menstrual Cycle Prediction for AI Agents

Set up Menstrual Cycle Prediction for AI Agents 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 →
Use it in Google Sheets or ExcelA =VERVE() formula fills a column — no script, no export, recalculates in place.VerveSheets →Reference →

Frequently asked questions

Do I have to tell the agent to use MenstrualCyclePredictionforAIAgents?

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 VerveContext 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 sources

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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