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Ovulation Calculation for AI Agents

Calculate ovulation dates and fertile window

OperationalCredits 2 per callp50 191msLifestyle

Overview

Includes current cycle status, days until ovulation, and educational information about cycle phases, perfect for fertility tracking and family planning applications.

Live Test Ovulation Calculation for AI Agents Source →

The tool

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

You do not name the tool yourself; the model picks it. Asking about 2024-01-01 in the terms this source covers is enough for it to reach for OvulationCalculationforAIAgents 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
last_periodRequiredstringFirst day of last menstrual period (YYYY-MM-DD)
date
cycle_lengthOptionalintegerAverage menstrual cycle length in days
default 28 · range 21–35

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": {
    "last_period": "2024-01-01",
    "cycle_length": 28,
    "ovulation": {
      "date": "2024-01-15",
      "days_from_last_period": 14
    },
    "fertile_window": {
      "start": "2024-01-10",
      "end": "2024-01-15",
      "duration_days": 6
    },
    "most_fertile_days": {
      "start": "2024-01-13",
      "end": "2024-01-15",
      "duration_days": 3
    },
    "fertile_days": [
      {
        "date": "2024-01-10",
        "day_relative_to_ovulation": -5,
        "fertility_level": "medium",
        "description": "Fertile"
      },
      {
        "date": "2024-01-11",
        "day_relative_to_ovulation": -4,
        "fertility_level": "medium",
        "description": "Fertile"
      },
      {
        "date": "2024-01-12",
        "day_relative_to_ovulation": -3,
        "fertility_level": "medium",
        "description": "Fertile"
      },
      {
        "date": "2024-01-13",
        "day_relative_to_ovulation": -2,
        "fertility_level": "high",
        "description": "Most fertile"
      },
      {
        "date": "2024-01-14",
        "day_relative_to_ovulation": -1,
        "fertility_level": "high",
        "description": "Most fertile"
      },
      {
        "date": "2024-01-15",
        "day_relative_to_ovulation": 0,
        "fertility_level": "high",
        "description": "Most fertile"
      }
    ],
    "next_period": {
      "date": "2024-01-29",
      "days_from_last_period": 28
    },
    "cycle_phases": {
      "follicular_phase": {
        "duration_days": 14,
        "description": "From first day of period to ovulation"
      },
      "ovulation": {
        "duration_days": 1,
        "description": "Egg is released from ovary"
      },
      "luteal_phase": {
        "duration_days": 14,
        "description": "From ovulation to next period"
      }
    },
    "current_status": {
      "current_phase": "Menstruation",
      "is_fertile": false,
      "days_until_ovulation": -701,
      "days_until_next_period": -687
    },
    "disclaimer": "This calculator provides estimates only. Actual ovulation may vary. Consult a healthcare provider for medical advice."
  }
}

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
last_periodstring2024-01-01The first day of the last menstrual period provided
cycle_lengthnumber28The average menstrual cycle length in days
ovulationobject{…}Estimated ovulation date and how many days into the cycle it falls
ovulation.datestring2024-01-15Calculated ovulation date in YYYY-MM-DD format
ovulation.days_from_last_periodPremiumnumber14Number of days from last period to ovulation
fertile_windowobject{…}Range of days conception is possible, with its length
fertile_window.startPremiumstring2024-01-10Start date of the fertile window period
fertile_window.endPremiumstring2024-01-15End date of the fertile window period
fertile_window.duration_daysPremiumnumber6Total duration of fertile window in days
most_fertile_daysobject{…}The narrower range with the highest chance of conception
most_fertile_days.startPremiumstring2024-01-13Start date of the most fertile days period
most_fertile_days.endPremiumstring2024-01-15End date of the most fertile days period
most_fertile_days.duration_daysPremiumnumber3Duration of the most fertile days in days
fertile_daysPremiumarray[6]Array of daily fertility data with levels and descriptions
fertile_days.0.datePremiumstring2024-01-10Date of the fertile day in YYYY-MM-DD format
fertile_days.0.day_relative_to_ovulationPremiumnumber-5Days relative to ovulation date (negative before, positive after)
fertile_days.0.fertility_levelPremiumstringmediumFertility level classification: low, medium, high
fertile_days.0.descriptionPremiumstringFertileHuman-readable description of fertility status for day
next_periodobject{…}Estimated start of the next period and how many days away it is
next_period.datePremiumstring2024-01-29Estimated date of the next menstrual period
next_period.days_from_last_periodPremiumnumber28Days from last period to expected next period
cycle_phasesobject{…}The phases of the cycle with their length and what happens in each
cycle_phases.follicular_phaseobject{…}From the first day of the period to ovulation
cycle_phases.follicular_phase.duration_daysPremiumnumber14Duration of follicular phase in days
cycle_phases.follicular_phase.descriptionPremiumstringFrom first day of period to ovulationDescription of the follicular phase
cycle_phases.ovulationobject{…}The day the egg is released
cycle_phases.ovulation.duration_daysPremiumnumber1Duration of ovulation phase in days
cycle_phases.ovulation.descriptionPremiumstringEgg is released from ovaryDescription of the ovulation phase
cycle_phases.luteal_phaseobject{…}From ovulation to the start of the next period
cycle_phases.luteal_phase.duration_daysPremiumnumber14Duration of luteal phase in days
cycle_phases.luteal_phase.descriptionPremiumstringFrom ovulation to next periodDescription of the luteal phase
current_statusobject{…}Where today falls in the cycle, and whether it is a fertile day
current_status.current_phasePremiumstringMenstruationCurrent phase of menstrual cycle relative to today
current_status.is_fertilePremiumbooleanfalseWhether the user is currently in the fertile window
current_status.days_until_ovulationPremiumnumber-701Days until ovulation from today (negative if past)
current_status.days_until_next_periodPremiumnumber-687Days until next period from today (negative if past)
disclaimerstringThis calculator provides estimates only. Actual ovulation may vary. Consult a healthcare provider for medical advice.Medical disclaimer regarding calculator 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 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 disclaimer: 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

Fertility Tracking
Build fertility tracking applications with accurate ovulation predictions based on cycle length and last period date
Conception Planning
Calculate conception probability windows and most fertile days to help users plan or prevent pregnancy
Menstrual Health
Create menstrual health apps with ovulation tracking, fertile window identification, and cycle insights
Family Planning
Provide family planning tools with science-based ovulation calculations and fertility awareness features

Other ways to use Ovulation Calculation for AI Agents

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

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