APIbase

Browse GUS Poland BDL Subject Tree

gus-poland.reference.subjects

Read-onlyIdempotent

Browse Poland's GUS Local Data Bank topic hierarchy to list root categories or child subjects via parent_id and find leaf subjects for variable lookup.

Instructions

Browse the topic hierarchy of Poland's official Local Data Bank (Bank Danych Lokalnych, GUS statistics office) — prices, demography, finance, environment, labour market, and more. Omit parent_id to list the 33 root topics, or pass a parent_id to list its children. Leaf subjects (has_variables=true) can be passed to gus-poland.variables. Data: bdl.stat.gov.pl (GUS BDL API v1), no auth required.

Input Schema

Name	Required	Description
`page`	No	Zero-based page number (default 0).
`page_size`	No	Results per page, 1-100 (default 20).
`parent_id`	No	BDL subject-tree node id to list children of (e.g. "K15" for PRICES, "G186" for a sub-topic). Omit to list the 33 root-level topic categories.

Output Schema

Name	Required	Description	Default
`error`	No	Present only when the call failed. Includes error code, message, request_id, and any provider-specific extras.
`result`	No	Tool response payload. Shape varies per tool — consult the tool description and inputSchema. May be an object, array, string, or number depending on the upstream provider response.

Schema Changelog

Changes observed during successful MCP inspections.

Addedv2.2.0Oct 29, 2026

TDQS

A4.5/5.0

Behavior4/5

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

Annotations already declare the operation read-only, open-world, idempotent, and non-destructive. The description goes beyond those by naming the upstream data source, stating that no auth is required, and revealing the has_variables leaf marker; it omits rate-limit or pagination behavior, though pagination is already documented in the schema.

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?

Every sentence earns its place: purpose, root-vs-child navigation, leaf-to-variables routing, and data source/auth. The key usage instructions are front-loaded before source details, with no filler.

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?

For an optional-parameter browse tool, the definition is complete: output schema covers return shape, annotations cover safety, and the description covers navigation, source, and the next sibling to call. Nothing needed to invoke it correctly is missing.

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?

All three parameters are described in the schema, including parent_id's omit-to-root behavior and concrete examples, and the description mostly restates that. Since schema coverage is 100%, the prose adds little parameter-level meaning beyond reinforcing the parent_id semantics.

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 and resource: 'Browse the topic hierarchy' of Poland's GUS Local Data Bank. It lists representative domains and then separates this navigation tool from gus-poland.variables by stating that leaf subjects are passed to that sibling tool.

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?

It provides exact selection logic: omit parent_id to get the 33 root topics, pass parent_id for children, and route leaf subjects to gus-poland.variables. This tells an agent both when to call the tool and what to do after the result, which is more than most sibling definitions provide.

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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