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

With no annotations, the description carries full responsibility for behavioral disclosure. It only mentions billing per call, but does not state whether it is read-only, what data it returns, or any side effects. The parameter hint about countries is in the schema but not elaborated in the description.

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 extremely concise—two short sentences with no filler or redundant information. It is well-structured but perhaps overly sparse, though not verbose.

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?

Given the simplicity of the tool (one optional param, no output schema), the description still fails to explain what the tool does or what results to expect. It lacks essential context for an agent to correctly invoke and interpret the tool, despite the schema providing some information.

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 has 100% coverage for the only parameter 'q', with a useful hint 'Leave blank to get countries'. The description adds no extra parameter context, but high schema coverage sets a baseline of 3.

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 'Locations Group: Explore' is vague and does not clearly state the tool's function. It implies some exploration of locations but lacks a specific verb or resource description. It doesn't differentiate from sibling tools beyond the name.

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?

There is no guidance on when to use this tool versus alternatives. The description provides no context about use cases or exclusions, such as when to prefer a different location-related tool.

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