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

Annotations already declare readOnly, non-destructive, and idempotent. The description adds minimal behavioral context—only that it 'details' a category, which is consistent with annotations. It does not discuss error handling, response format, or side effects, but given the annotations cover safety, the bar is lower.

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 concise—two short sentences. It front-loads the main purpose and then adds bulk support as a secondary note. No redundant or irrelevant information is present.

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 GET-by-id tool, the description provides the endpoint, mentions bulk behavior, and includes the main parameter. However, it omits the account parameter, does not describe the output, and does not address edge cases. It is adequate but not fully comprehensive for all context.

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 provides no descriptions for id, ids, or account. The description explains id (by id) and ids (bulk support), but leaves account unexplained. It does not clarify types, constraints, or relationships between parameters, so parameter semantics are only partially covered.

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's purpose: 'Detalha uma categoria por id' (Details a category by id) and specifies the HTTP method and endpoint (GET /categories/{id}). This distinguishes it from sibling tools like mercadolivre_list_categories, which likely fetch multiple categories.

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 mentions bulk support ('accepts ids for batched execution'), hinting at usage for multiple IDs, but it does not explicitly state when to use this tool over alternatives, nor does it give prerequisites or exclusions. The 'when-to-use' is only implicit from the tool name and purpose.

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