Galaxy Cluster Catalogs MCP Server

fetch_cluster_catalog

Download one galaxy-cluster catalogue and write a harmonized CSV with redshift, mass, and signal-to-noise cuts, producing the file path all other catalogue tools require.

Instructions

Download one cluster catalogue (first use only) and write a harmonised CSV with cuts applied.

Use this first: every other catalogue tool takes the CSV path it writes.
Columns: name, ra, dec [deg], z, z_err, M500 [1e14 Msun, M500c], M500_err_lo,
M500_err_hi, snr (survey-native statistic), survey, dataset. NaN = missing.

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": {
      "output_dir": "<output_dir>",
      "dataset": "<dataset>"
    },
    "name": "fetch_cluster_catalog"
  }
}

Input Schema

Name	Required	Description
`z_max`	No	Maximum redshift.
`z_min`	No	Minimum redshift (drops entries without z).
`dataset`	Yes	Catalogue key: psz2, spt_sz, sptpol_100d, spt_ecs, spt3g_5yr, act_dr6, erass1, erass1_cosmo (see list_clusters_datasets).
`snr_min`	No	Minimum native detection statistic (xi / SNR / EXT_LIKE).
`m500_max`	No	Maximum M500c in 1e14 Msun.
`m500_min`	No	Minimum M500c in 1e14 Msun.
`output_dir`	Yes	Directory for output files (created if missing).
`require_mass`	No	Keep only entries with an M500 estimate.
`require_redshift`	No	Keep only entries with a redshift.

Output Schema

Name	Required	Description	Default
`files`	Yes
`status`	Yes
`message`	Yes
`metadata`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Nov 6, 2026

TDQS

A5/5.0

Behavior5/5

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

Since no annotations are provided, the description must carry the behavioral burden. It is highly effective in detailing the output column structure, the specific units (e.g., M500 in 1e14 Msun), and handling missing data (NaN).

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 tool definition is highly efficient. It front-loads the essential workflow instruction ('Use this first') before detailing the specific output structure, ensuring immediate understanding of its purpose and constraints.

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

Completeness5/5

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

Given the high parameter count and the complex file-writing operation, the description is maximally complete. It covers the 'what,' 'how,' and 'where' of the data processing lifecycle without needing an output schema.

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

Parameters5/5

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

The description goes far beyond the schema by defining the resultant data's meaning and units, such as explaining that M500 is in 1e14 Msun and defining the survey-native statistic (snr). This context is crucial for interpreting the tool's output data payload.

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 clearly defines the tool's role: downloading a catalogue, applying harmonizing cuts, and writing a CSV. This specific action distinguishes it from the surrounding processing and prediction tools.

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

Usage Guidelines5/5

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

The description gives explicit guidance on workflow, stating that this tool must be used first because other catalogue tools rely on the CSV path it creates. This prevents incorrect sequencing of tool calls.

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