country_by_language

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 fails to mention output format, error handling (e.g., invalid language), or source details beyond 'REST Countries'. The agent is left unaware of what the tool returns or how it behaves.

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 (7 words) that front-loads the core purpose. While concise, it sacrifices essential details; however, it earns a 4 for being free of unnecessary content and directly stating the action.

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 absence of output schema and annotations, the description should compensate by explaining input format and output shape. It does not; the agent cannot determine what language format to use or what response to expect, making the tool incomplete for reliable use.

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 description adds no meaning to the 'language' parameter beyond what the schema states (a string). With 0% schema description coverage, the parameter is completely undocumented in both schema and description, leaving the agent uncertain about valid input (e.g., language name, code, casing).

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 'Get countries by language from REST Countries' clearly states the verb (get), the resource (countries), and the filtering attribute (language). It distinguishes itself from sibling tools like country_by_code or country_by_region by specifying the unique query parameter.

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 provided on when to use this tool versus alternatives (e.g., country_by_name, country_by_currency). It does not specify language format expectations (name vs. ISO code) or any prerequisites, leaving the agent to infer usage context.

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