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

Annotations already cover read-only, idempotent, non-destructive. The description adds real behavioral detail beyond them: results are sorted by highest commission, and the aggregate conversion/EPC only count marketplaces with clicks — a caveat that would otherwise cause misinterpretation.

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?

Two tight sentences; the metric list and per-marketplace scope come first, with the conversion caveat trailing. Dense but every clause carries information.

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?

With no output schema, the description usefully enumerates returned fields and the sort order. Dates/period definition is left entirely to the schema, which is acceptable given full coverage.

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%, documenting days/start_date/end_date including defaults. The description adds no parameter guidance, so baseline 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?

Names the resource (period overview) and enumerates the exact metrics returned, plus the per-marketplace dimension. Clearly distinguishable from sibling breakdown tools, which slice by a single axis.

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?

'É o ponto de partida para entender a conta' implies it should be called first, which is useful positioning. But it doesn't name alternatives or exclusions — e.g. when to prefer painel_compare_periods or painel_get_monthly_growth.

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