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

Annotations already declare readOnlyHint=true, idempotentHint=true, openWorldHint=true, and destructiveHint=false, covering the safety profile. The description adds a useful billing estimate ('$0.012 USD') and notes that pricing is usage-based and may vary, which is behavioral context beyond the annotations. However, it does not describe rate limits, authentication needs, or return format details, so it remains a modest addition.

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 core purpose is front-loaded in a single sentence, and the pricing note is clearly demarcated as supplementary information. The text is short and every sentence serves a purpose, though the phrase 'by calling this API' is slightly redundant.

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 zero-parameter, read-only list endpoint with an output schema already defining the return shape, the description is nearly complete. It states what is returned and includes cost context, but it could mention when to use this tool relative to its siblings, which is a minor gap.

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 tool takes zero parameters, so there are no parameter semantics to clarify. Per the rubric, a zero-parameter tool earns a baseline of 4, and the description appropriately does not invent parameter details.

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 clearly states the tool returns the list of supported Google Shopping languages, which is a specific resource and verb. It implicitly distinguishes from siblings like get_dataforseo_merchant_amazon_languages and get_dataforseo_merchant_google_locations by naming 'Google Shopping languages', but it does not explicitly contrast with those alternatives.

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 offers no guidance on when to use this tool versus alternatives, nor does it mention prerequisites or exclusions. It simply states the outcome of calling the API, leaving usage decisions entirely to inference.

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