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

With no annotations, the description carries the full burden of disclosure. 'List' implies a read-only operation, and the catalog scope adds some context, but it does not disclose ordering, return format, authentication, or potential empty results. For a zero-parameter list tool, this is minimally viable but not rich.

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 is front-loaded with the verb and resource. Every word earns its place, and there is zero waste.

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 tool is extremely simple with no parameters and no output schema. The description explains what it does and the catalog scope, which is sufficient for an agent to select and invoke it correctly. There is no missing information that would cause confusion.

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, so the schema already covers everything. The description adds no parameter-specific detail, but the baseline for zero parameters is 4, and no further explanation is necessary.

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 clear verb 'List' with a specific resource 'countries' and scope 'available in the 1001locals catalog'. It clearly distinguishes from siblings like list_categories and list_cities, making the tool's purpose unambiguous.

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 clear context by indicating the catalog scope, which implies when to use it (when you need the catalog's countries). It does not explicitly mention alternatives or exclusions, but the simplicity of the tool and distinct sibling names make the usage context clear.

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