list_languages

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

No annotations are provided, so the description carries the full burden. It discloses a cost of $0.001 USDC via x402, which is useful, but it does not mention return format, whether the list is sorted, paginated, or cached, or any access requirements beyond payment.

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, front-loaded sentence that conveys the core action and cost. It is concise and easy to read, though the 'Data & Weather tool' fragment is somewhat unrelated to languages and could be considered 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 tool with no output schema and no annotations, the description is too minimal. It does not clarify what kind of languages are listed, what the response looks like, or whether any optional parameters (e.g., language code filter) exist. The cost disclosure is helpful but insufficient for an agent to confidently invoke the tool.

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 input schema contains only a generic 'params' object with 100% schema coverage, but this provides no meaningful parameter details. The description adds no parameter information, and the tool likely requires no specific arguments. Baseline 3 applies because the schema technically describes the only parameter, yet it is a hollow envelope.

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 states 'list languages,' which is a specific verb+resource combination that clearly identifies the tool's action. It distinguishes from sibling tools like list_countries and list_currencies by the resource 'languages,' though it doesn't specify whether these are spoken, programming, or platform languages.

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 no guidance on when to use this tool versus alternatives. The 'Data & Weather tool' label is a category tag, not a usage guideline, and does not explain scenarios where list_languages is preferred over sibling list tools.

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