Daylight Duration Grounding Data

Overview

Returns detailed information including day of year, sunrise/sunset times, and formatted daylight duration, perfect for solar energy, agriculture, and travel applications.

Live Test Daylight Duration Grounding Data Source →

The tool

Once your client is connected to the VerveContext server, this appears in its tool list as DaylightDurationGroundingData. 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.

{
  "name": "DaylightDurationGroundingData",
  "arguments": {
    "latitude": "40.7128",
    "longitude": "-74.006"
  }
}

You do not name the tool yourself; the model picks it. Asking about 40.7128 in the terms this source covers is enough for it to reach for DaylightDurationGroundingData 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"
    }
  }
}

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.

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.

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{
  "status": "ok",
  "error": null,
  "data": {
    "date": "2024-06-21",
    "location": {
      "latitude": 40.7128,
      "longitude": -74.006
    },
    "condition": "Normal",
    "description": "Standard sunrise and sunset",
    "sunrise": "09:25:09",
    "sunset": "24:30:44",
    "daylight_duration": {
      "total_minutes": 905.58,
      "hours": 15,
      "minutes": 5,
      "formatted": "15:05:00"
    },
    "day_of_year": 173,
    "is_valid": true
  }
}

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.

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 description: 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.

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

Solar Optimization

Calculate daylight hours for solar panel optimization and energy production forecasting based on geographic location

Activity Planning

Plan outdoor activities and events based on accurate sunset and sunrise times for any location and date

Weather Apps

Build weather and astronomy applications with precise daylight duration calculations and solar position data

Photography Scheduling

Schedule photography sessions based on golden hour timing, blue hour, and optimal natural lighting conditions

Other ways to use Daylight Duration Grounding Data

Set up Daylight Duration 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.

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