Astronomer MCP Server

list_cosmic_structures

Lists galaxies, dwarf galaxies, and galaxy clusters in Astronomer with star system counts, supporting name or description filtering and pagination.

Instructions

List cosmic structures (galaxies, dwarf galaxies, galaxy clusters) registered in Astronomer with star system counts.

Tool call template

This tool declares no required parameters. Add optional parameters from the input schema as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {},
    "name": "list_cosmic_structures"
  }
}

Input Schema

Name	Required	Description
`q`	No	Filter cosmic structures by name or description substring
`limit`	No	Pagination limit (default: 50)
`offset`	No	Pagination offset (default: 0)
`include_star_systems`	No	Include star systems associated with each cosmic structure

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.0.0Nov 13, 2026

TDQS

A3.5/5.0

Behavior3/5

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

With no annotations, the description carries more burden, but it does disclose that results are registered cosmic structures and include star system counts. It does not explain pagination behavior, ordering, or how the star system counts relate to the include_star_systems parameter, leaving some behavioral ambiguity.

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

Conciseness5/5

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

The description is a single front-loaded sentence with no filler. It states the verb, resource, examples, and the count-related aspect immediately.

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?

For a parameterized list tool with no output schema, the description should clarify return shape, pagination behavior, and the effect of include_star_systems. It gives the high-level result content but leaves those specifics to the schema or inference.

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

Parameters3/5

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

Schema description coverage is 100%, so the schema already documents q, limit, offset, and include_star_systems. The description adds only the resource categories and the output notion of star system counts, without clarifying how include_star_systems changes the result.

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

Purpose5/5

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

The description uses a specific verb ('List') and a specific resource ('cosmic structures'), then clarifies the resource with examples: galaxies, dwarf galaxies, and galaxy clusters. That scope distinguishes it from sibling tools such as get_cosmic_structure, list_celestial_bodies, and list_star_systems.

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

Usage Guidelines2/5

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

The description does not state when to use this list tool versus alternatives such as get_cosmic_structure or list_star_systems, nor does it mention exclusions or prerequisites. Usage is only implied by the verb 'List'.

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

Deploy Server