Planet Positions Grounding Data for AI Agents
The tool
Ground agents in verifiable planetary coordinates and distances so astronomy answers rest on computed ephemeris data, not recall.
Once your client is connected to the VerveContext MCP server, this appears in its tool list as PlanetPositionsGroundingDataforAIAgents. 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.
{
"name": "PlanetPositionsGroundingDataforAIAgents",
"arguments": {
"lat": "37.7749",
"lon": "-122.4194",
"planet": "mars"
}
}What that looks like in a conversation
You don't name the tool — 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.
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 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 |
|---|---|---|---|
latRequired | number | 37.7749 | The latitude of the observer |
lonRequired | number | -122.4194 | The longitude of the observer |
planetRequired | string | mars | The planet to get position data for One of: sun, moon, mercury, venus, mars, jupiter, saturn, uranus. |
datePremium | string | 01-16-2026 | The date to get planetary position data for (MM-DD-YYYY) |
time | string | 21:00 | The time of day for the calculation (HH:mm format, 24-hour). Defaults to 00:00 if not provided |
alt | number | 0 | The altitude of the observer in meters |
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.
{
"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
}
}
}Fields
| Field | Type | Example | Description |
|---|---|---|---|
planet | string | Name of the celestial body being observed | |
isBelowHorizon | boolean | Whether the planet is below horizon at observation location | |
date | string | Observation date and time in ISO 8601 format | |
observer | object | ||
└ observer.latitude | number | Observer latitude in decimal degrees | |
└ observer.longitude | number | Observer longitude in decimal degrees | |
rightAscensionPremium | object | Right ascension coordinates of the planet | |
└ rightAscension.hoursPremium | number | Right ascension hours component (0-23) | |
└ rightAscension.minutesPremium | number | Right ascension minutes component (0-59) | |
└ rightAscension.secondsPremium | number | Right ascension seconds component (0-59) | |
declinationPremium | object | Declination coordinates of the planet | |
└ declination.degreesPremium | number | Declination degrees component (-90 to 90) | |
└ declination.minutesPremium | number | Declination minutes component (0-59) | |
└ declination.secondsPremium | number | Declination seconds component (0-59) | |
distancePremium | object | Distance to the planet in various units | |
└ distance.kmPremium | number | Distance to planet in kilometers | |
└ distance.lightTravelSecondsPremium | number | Light travel time in seconds from planet | |
└ distance.astronomicalUnitsPremium | number | Distance in astronomical units (AU) | |
siderealTimePremium | object | Local sidereal time at observation | |
└ siderealTime.hoursPremium | number | Local sidereal time hours component (0-23) | |
└ siderealTime.minutesPremium | number | Local sidereal time minutes component (0-59) | |
└ siderealTime.secondsPremium | number | Local sidereal time seconds component (0-59) | |
hourAnglePremium | object | Hour angle from the meridian | |
└ hourAngle.hoursPremium | number | Hour angle hours component from meridian | |
└ hourAngle.minutesPremium | number | Hour angle minutes component from meridian | |
└ hourAngle.secondsPremium | number | Hour angle seconds component from meridian | |
vectorsPremium | object | Position vector components | |
└ vectors.xPremium | number | X component of planet position vector | |
└ vectors.yPremium | number | Y component of planet position vector | |
└ vectors.zPremium | number | 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 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 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 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 source isn't part of VerveContext. Check the catalog. |
429 | Brief rate limit. Retrying after a moment succeeds. |
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.
Frequently asked questions
Do I have to tell the agent to use PlanetPositionsGroundingDataforAIAgents?
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.