AstroMCP

asteroids_at

Read-onlyIdempotent

Find known solar-system objects near a sky position at a UTC time, returning names, classes, magnitudes, separation, and motion for quick identification.

Instructions

Known solar-system objects near a position at a given time (IMCCE SkyBoT, geocentric): name, class, V mag, separation, motion. epoch_iso is UTC, e.g. '2026-10-20T03:15:00'.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "ra": "<ra>",
      "dec": "<dec>",
      "epoch_iso": "<epoch_iso>"
    },
    "name": "asteroids_at"
  }
}

Input Schema

Name	Required	Description	Default
`ra`	Yes
`dec`	Yes
`epoch_iso`	Yes
`radius_arcsec`	No

Output Schema

Name	Required	Description	Default
No arguments

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Nov 3, 2026

TDQS

B3.4/5.0

Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnly=true, idempotent=true, openWorld=true, so the safety profile is covered. The description adds genuinely non-obvious context: the data source is IMCCE SkyBoT and results are geocentric, plus what fields come back. It omits limits (max rows, how a large radius is handled) but for a read-only query tool this is solid added value.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Two sentences, front-loaded with the resource and scope, with the source/frame parenthetical doing real work. The return-field list ("name, class, V mag, separation, motion") is mildly redundant given an output schema exists, but it is compact enough not to be waste.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness3/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

An output schema exists so return values needn't be spelled out, and annotations cover safety, leaving parameter meaning as the main gap. An agent still lacks coordinate units and the meaning of radius_arcsec, and cannot tell whether the result set includes comets or natural satellites despite the tool name saying asteroids.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters2/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 0%, so the description carries the full burden. It explains epoch_iso precisely (UTC, with a worked example) but leaves ra/dec units and expected ranges unstated, and radius_arcsec — including its 30 arcsec default and what it governs — is never mentioned despite being the parameter that defines "near".

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific resource and scope: known solar-system objects near a position at a given time, with the upstream service (IMCCE SkyBoT) and frame (geocentric) named. That implicitly separates it from stellar/transient siblings like simbad or ztf_objects_near, though it never names an alternative explicitly. Note the mild mismatch between the tool name (asteroids_at) and the broader description ("solar-system objects").

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The phrase "near a position at a given time" implies the invocation condition, but there is no explicit when-to-use guidance, no prerequisites, and no routing to or away from siblings such as whats_here or ztf_objects_near. Usage is inferable rather than stated.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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