uis_list_countries

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

Annotations already declare this as a read-only, idempotent, open-world, non-destructive operation. The description adds useful behavioral context: it explains that the output is a Markdown list of ISO codes and country names, and it distinguishes between NATIONAL and REGIONAL entities, including examples of regional aggregates. It does not cover auth requirements or rate limits, but the annotations carry the safety profile.

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

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

The description is front-loaded with purpose and return value, then adds practical examples and entity-type context. The Args and Returns sections are compact, though the Args line slightly conflates nesting and direct arguments. Overall it is efficient with little wasted text.

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

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

An output schema exists, so the description need not document return values, yet it helpfully summarizes the Markdown list format. Annotations cover the safety profile, and the description covers entity types, filtering, and the purpose of the returned codes. A minor gap is the lack of explicit nesting guidance for the params object.

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

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

The schema itself provides detailed descriptions for the nested search and entity_type properties, including allowed entity_type values and caveats about unsupported values. The tool description adds marginal value by naming both optional filters and giving examples of regional aggregate types, but it misleadingly presents search and entity_type as direct arguments rather than as fields nested inside the required params object. Given the schema already does the heavy lifting, this is adequate but imperfect.

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

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

The description states a specific verb and resource: it lists available countries and regions in the UNESCO UIS database. It also clarifies that the tool returns ISO 3166-1 alpha-3 codes needed for data queries, which distinguishes it from indicator-listing or data-retrieval siblings. However, it does not explicitly name or contrast itself with any sibling tool, so it falls short of the highest clarity tier.

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

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

The description implies usage by saying the returned ISO codes are needed for data queries, and it mentions optional filtering via search and entity_type. It does not state when to use this tool versus alternatives such as uis_list_indicators or uis_compare_countries, nor does it provide any when-not-to-use guidance.

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