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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the safety profile is covered. The description adds two useful behavioral facts beyond them: pricing uses 'o mesmo motor do site' (consistency with the website) and freight is excluded, but it says nothing about error handling for invalid SKUs or limits.

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 core computation is front-loaded and the freight exclusion is a short, high-value caveat. Nothing is wasted.

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 3-parameter read-only calculation with a fully documented schema and no output schema, the description is nearly sufficient: it names the returned quantities and the scoping caveat. It could be marginally stronger by noting the recordings default/bounds interplay, but nothing essential is missing.

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 coverage is 100%, so the schema already documents produto (SKU/ID), quantidade and aplicacoes including the 0–4 bounds and default. The description only restates that price depends on quantity and recordings, adding no format or edge-case detail beyond the schema.

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 states a specific verb (calcula) and concrete outputs (preço unitário e total) scoped to a product, quantity and number of gravações. It implicitly distinguishes itself from calcular_frete by declaring 'Não inclui frete', though it never names the sibling directly.

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?

Usage is implied rather than stated: the agent can infer this is the pricing tool and that shipping must be obtained elsewhere, but there is no explicit 'use this when' or routing to calcular_frete or buscar_produtos.

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