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

With no annotations, the description carries the burden of behavioral disclosure. It does mention the optional language arguments and allowed values (en|lt|pl|de), but it omits return format, default language behavior, and whether lang and language are aliases. The read-only nature is clear from the verb, but more operational detail would improve transparency.

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 concise sentence with the purpose front-loaded and argument details following. Every word contributes value, with no redundant or technical filler.

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?

For a simple list tool with two optional parameters and no output schema, the description is largely complete. It states the purpose, the argument names, and accepted values. It could mention the response shape or sorting, but those are not essential for basic invocation. The absence of annotations slightly lowers completeness, but not drastically.

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 0%, so the description must compensate. It does add the allowed values 'en|lt|pl|de' for both lang and language, which goes beyond the bare schema. However, it does not clarify the relationship or precedence between the two parameters, leaving some ambiguity.

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' with a clear resource 'covered route countries', making the tool's purpose unambiguous. It distinguishes itself from sibling tools like list_languages and get_route by focusing on country coverage.

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 usage when country coverage for routes is needed, but it provides no explicit guidance on when to use this tool versus alternatives. No exclusions or alternative tool references are given, so the usage context is only implicit.

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