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

There are no annotations, so the description must carry the full behavioral burden. It doesn't disclose whether this is a read-only operation, how results are returned, whether pagination or rate limits apply, or what 'compare' actually entails (e.g., side-by-side metrics). The single sentence provides essentially no behavioral context.

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 short, which might be seen as concise, but it is also under-specified. It is front-loaded with the core action but lacks necessary context. For a comparison tool, two words is insufficient.

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 complexity of a comparison tool, the lack of annotations, no output schema, and only one parameter with full schema coverage, the description is incomplete. It should explain what regions are compared, what metrics are returned, and how to interpret the results. Without that, the agent cannot confidently invoke it.

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% description coverage for the single 'range' parameter, including an enum and a description. The tool description adds nothing beyond that, so the baseline score of 3 is appropriate. It does not provide examples or default behavior for the range parameter.

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 'Compare regions' states a verb and a resource, but it is terse and does not distinguish this tool from other comparison siblings such as players_compare, clans_compare, or tanks_compare. There are also several ambiguous 'og_*' siblings, so the scope is unclear. The name 'servers_compare' is also not echoed in the description, adding confusion about what exactly is being compared.

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?

No guidance is given about when to use this tool versus alternatives. It doesn't mention what happens without parameters, nor does it reference sibling tools or prerequisites. An agent would have to guess the intended use case.

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