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

Annotations already declare readOnlyHint=true, and the description's 'search and compare' wording is consistent with a read-only operation. The description adds useful scoping about what content is covered (Básico, Profissional, Construtora Ilimitado) but does not disclose additional behavioral details such as output shape or pagination; the output schema reduces the need for those details.

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, focused sentence with no filler or repetition. It front-loads the action and resource, then names the exact plans, making it very efficient for an agent to parse.

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 search tool with one optional parameter, a readOnly annotation, and an output schema, the description is largely complete. The only minor gap is that no explicit usage guidance is given relative to sibling tools, but the domain is distinct enough that this does not materially hurt completeness.

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 100%, so the single parameter plan_name is already fully documented with examples and the 'all' option. The tool description does not add parameter-level meaning beyond what the schema provides, so the baseline of 3 applies.

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 names a specific action ('Pesquisa e compara') and a concrete resource (FinGo commercial plans, capabilities, and resources), listing the plan names. This clearly distinguishes it from the siblings get_financial_summary and get_sinapi_info, which target different domains.

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 makes it clear this tool is for searching and comparing FinGo plans, which gives an agent strong contextual guidance for when to invoke it. It does not explicitly mention alternatives or exclusions, but the sibling names and the description's domain focus make the usage context unambiguous.

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