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

Annotations already provide readOnlyHint, and the description adds meaningful behavioral context beyond that: it returns exactly 18 region records and by default excludes 1,098 crossover pages unless type is set. This helps set accurate expectations, though pagination and filtering behavior are not described.

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 three short, information-dense sentences with the main purpose front-loaded, a concrete example, and no filler. Every sentence contributes meaning.

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?

The description covers what is returned, the default filtering behavior, and how to request crossover pages, which makes basic invocation feasible. However, with no output schema and several undocumented input parameters, the description is not complete enough for an agent to confidently use sorting, querying, or pagination without additional inference.

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?

Schema description coverage is only 33%, and the description must compensate, but it only adds high-level meaning for sort ('provider/API count') and type. The q, page, limit, and sort parameters remain effectively undocumented in both schema and description, making it hard for an agent to know valid values or formats.

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?

Description clearly specifies a browse/list action over geographic regions and tells the agent that the 18 region records are the primary results, while region-industry crossover pages are a separate collection. This is specific enough to understand the tool's core use, but it does not explicitly distinguish it from sibling tools like find_countries or get_region.

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 provides useful guidance on the default region type and explains that crossover pages require the type parameter. However, it never states when to prefer this tool over sibling find/get tools or gives any when-not-to-use guidance, so the usage guidance remains largely implicit.

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