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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, covering the safety profile. The description adds little behavioral detail beyond 'Discovery rápido' and the input semantics; no return format or edge cases are described, so with annotations present this is acceptable.

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 sentence with no repetitive or irrelevant content. It front-loads the action and resource.

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 one-parameter search tool with read-only annotations, the description specifies the input, the output (the ticker), and the purpose. It omits details like multiple results or no-match behavior, but these are likely evident from the tool's design and sibling 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?

Schema description coverage is 0%, so the description must carry the parameter meaning. The phrase 'a partir de um trecho do nome/código' explains that the single required 'query' is a partial name or code, which is adequate for a single-parameter search tool.

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 'Resolve o código (ticker) de um ativo a partir de um trecho do nome/código' which clearly states the tool resolves an asset's ticker from a partial name/code. This distinguishes it from siblings like mercado_quote or mercado_list, as it's a discovery/search action.

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 indicates usage for quick discovery when only a fragment of the name or code is known. It does not explicitly name alternatives or exclusions, but the purpose implicitly sets it apart from quoting or listing tools.

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