ipums-mcp

nhgis_search_data_tables

Search NHGIS data tables by keyword to locate matching descriptions and universes. Specify a dataset for a comprehensive scan of all its tables.

Instructions

Search NHGIS data tables by keyword. If a dataset is specified, searches all tables within that dataset (comprehensive). Without a dataset, scans up to 2,500 tables across all datasets — recommend using nhgis_search_datasets first to find a relevant dataset, then scoping the search here. Matches against table description and universe.

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": {
      "keyword": "<keyword>"
    },
    "name": "nhgis_search_data_tables"
  }
}

Input Schema

Name	Required	Description	Default
`dataset`	No	Optional dataset identifier to scope the search (e.g. '2019_ACS5a'). Strongly recommended for comprehensive results.
`keyword`	Yes	Search term to match against table description and universe (case-insensitive)

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Aug 3, 2026

TDQS

A4.7/5.0

Behavior4/5

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

With no annotations, the description carries the full burden of disclosing behavior. It reveals the scan limit (up to 2,500 tables), the matching criteria, and that specifying a dataset yields comprehensive results. It stops short of detailing return format or pagination, but the provided behavioral context is strong for a search tool.

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 concise, front-loaded with the core purpose, and each sentence adds critical value: what it does, how scope changes behavior, and a concrete recommendation. No redundant wording.

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 no output schema, the description provides enough context for an agent to decide when to invoke and what to expect: searchable fields, scope limitations, and a recommended alternative workflow. It fully covers the tool's complexity and fits well within the sibling-tool ecosystem.

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

Parameters4/5

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

Schema coverage is 100%, and both parameters are already described. The description adds meaningful context beyond the schema: the 'dataset' parameter's impact on comprehensiveness and the keyword's matching scope. This enhances understanding of parameter usage, especially the recommended workflow.

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 ('Search') with a clear resource ('NHGIS data tables'), and immediately differentiates from sibling tools by focusing on data tables rather than datasets or time series tables. It also specifies matching fields (description and universe), leaving no ambiguity about the tool's function.

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 provides explicit guidance: without a dataset it scans up to 2,500 tables, and it recommends using nhgis_search_datasets first to scope the search. This directly addresses when to use this tool vs. alternatives and gives a clear workflow.

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