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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds behavioral context beyond annotations by specifying that only countries with listed businesses are included, and that the response contains a count and a directory address. It does not mention ordering or pagination, but for a simple no-parameter listing these are minor omissions.

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 a single sentence that front-loads the core purpose ('Every country with businesses listed on Nearwick') and immediately appends the two key output details. There is no filler, and every word 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?

With no output schema, the description carries the responsibility for explaining the return shape, and it does state the two main elements: business count and directory address. It does not specify sorting, pagination, or field names, which could matter for programmatic use, but for a simple directory list with no parameters the definition is reasonably complete.

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 tool has zero parameters, and the schema covers 100% of them trivially. Per the baseline rule, 0 params earns a 4. The description does not need to explain parameter semantics because there are none to explain.

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 uses a specific verb ('list') and resource ('countries'), and states exactly what is returned: every country with businesses on Nearwick, the business count per country, and the directory address. This clearly distinguishes it from sibling tools like get_business or search_businesses, which operate at the business or category level.

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 this tool is for retrieving a country-level directory, but it does not explicitly state when to use it over siblings or when not to use it. An agent can infer its purpose from the phrasing, but there is no direct guidance such as 'for business details, use get_business' or 'for searching, use search_businesses.' This is adequate but not explicit.

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