Overview
Pass observer latitude, longitude, and a chosen planet from Pluto to the Moon. The API calculates observation geometry with optional observer altitude and observation time, returning whether the target sits below the local horizon. Paid plans let you set specific dates and return right ascension, declination, distances, sidereal time, and Cartesian position vectors.
Live Test Planet Positions Grounding Data for AI Agents Source →
The tool
Once your client is connected to the VerveContext server, this appears in its tool list as PlanetPositionsGroundingDataforAIAgents. 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": "PlanetPositionsGroundingDataforAIAgents",
"arguments": {
"lat": "37.7749",
"lon": "-122.4194",
"planet": "mars"
}
}You do not name the tool yourself; the model picks it. Asking about 37.7749 in the terms this source covers is enough for it to reach for PlanetPositionsGroundingDataforAIAgents 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/mcpPer-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.
| Argument | Type | Description |
|---|---|---|
dateOptionalPremium | string | The date to get planetary position data for (MM-DD-YYYY) date |
timeOptional | string | The time of day for the calculation (HH:mm format, 24-hour). Defaults to 00:00 if not provided time |
latRequired | number | The latitude of the observer range -90–90 |
lonRequired | number | The longitude of the observer range -180–180 |
altOptional | number | The altitude of the observer in meters range 0–∞ |
planetRequired | string | The planet to get position data forsunmoonmercuryvenusmarsjupitersaturnuranus+2 |
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.
{
"status": "ok",
"error": null,
"data": {
"planet": "Moon",
"isBelowHorizon": false,
"date": "2025-04-15T10:37:00Z",
"observer": {
"latitude": 37.7749,
"longitude": -122.4194
},
"rightAscension": {
"hours": 15,
"minutes": 13,
"seconds": 11
},
"declination": {
"degrees": -23,
"minutes": 10,
"seconds": 56
},
"distance": {
"km": 402457.36,
"lightTravelSeconds": 1.342,
"astronomicalUnits": 0.003
},
"siderealTime": {
"hours": 16,
"minutes": 2,
"seconds": 42
},
"hourAngle": {
"hours": 0,
"minutes": 49,
"seconds": 31
},
"vectors": {
"x": -0.0016452947779903913,
"y": -0.0018463324771434563,
"z": -0.0010590407236111441
}
}
}
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.
| Field | Type | Example | Description |
|---|---|---|---|
planet | string | Moon | Name of the celestial body being observed |
isBelowHorizon | boolean | false | Whether the planet is below horizon at observation location |
date | string | 2025-04-15T10:37:00Z | Observation date and time in ISO 8601 format |
observer | object | {…} | The location the position was calculated for |
observer.latitude | number | 37.7749 | Observer latitude in decimal degrees |
observer.longitude | number | -122.4194 | Observer longitude in decimal degrees |
rightAscensionPremium | object | {…} | Right ascension coordinates of the planet |
rightAscension.hoursPremium | number | 15 | Right ascension hours component (0-23) |
rightAscension.minutesPremium | number | 13 | Right ascension minutes component (0-59) |
rightAscension.secondsPremium | number | 11 | Right ascension seconds component (0-59) |
declinationPremium | object | {…} | Declination coordinates of the planet |
declination.degreesPremium | number | -23 | Declination degrees component (-90 to 90) |
declination.minutesPremium | number | 10 | Declination minutes component (0-59) |
declination.secondsPremium | number | 56 | Declination seconds component (0-59) |
distancePremium | object | {…} | Distance to the planet in various units |
distance.kmPremium | number | 402457.36 | Distance to planet in kilometers |
distance.lightTravelSecondsPremium | number | 1.342 | Light travel time in seconds from planet |
distance.astronomicalUnitsPremium | number | 0.003 | Distance in astronomical units (AU) |
siderealTimePremium | object | {…} | Local sidereal time at observation |
siderealTime.hoursPremium | number | 16 | Local sidereal time hours component (0-23) |
siderealTime.minutesPremium | number | 2 | Local sidereal time minutes component (0-59) |
siderealTime.secondsPremium | number | 42 | Local sidereal time seconds component (0-59) |
hourAnglePremium | object | {…} | Hour angle from the meridian |
hourAngle.hoursPremium | number | 0 | Hour angle hours component from meridian |
hourAngle.minutesPremium | number | 49 | Hour angle minutes component from meridian |
hourAngle.secondsPremium | number | 31 | Hour angle seconds component from meridian |
vectorsPremium | object | {…} | Position vector components |
vectors.xPremium | number | -0.0016452947779903913 | X component of planet position vector |
vectors.yPremium | number | -0.0018463324771434563 | Y component of planet position vector |
vectors.zPremium | number | -0.0010590407236111441 | Z component of planet position vector |
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 isBelowHorizon: 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.
| Status | What it means |
|---|---|
400 / 422 | The arguments did not validate. The message names the offending one. |
401 | The OAuth session is invalid or expired — reconnect the server. |
403 | Blocked by a key restriction or an IP allow-list. Never a bad identity. |
404 | This source is not part of VerveContext. Check the catalog. |
429 | Out 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
- Stargazing Tour Scheduling
- When planning evening viewing sessions, astronomy guides check if target planets sit below the horizon at their field camp location and scheduled observation time.
- Telescope Mount Pointing
- Astrophotographers on paid plans calculate exact right ascension and declination coordinates to aim automated tracking mounts toward visible solar system targets.
- Astrology Chart Generation
- Natal chart software queries planetary bodies across specific dates on paid plans to map celestial positions for birth chart generation.
- Planetarium Display Sync
- To project accurate night sky exhibits, science museum kiosks query live planetary coordinates based on local building coordinates and viewing time.
Other ways to use Planet Positions Grounding Data for AI Agents
Set up Planet Positions Grounding Data 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.
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