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

Annotations already cover safety (readOnly, idempotent, closed-world), and the description adds genuinely non-obvious behavior: the statistic is computed from current stock plus sales in the last 90 days, and combinations with fewer than 3 devices are excluded. That explains why a query may yield no result — valuable context beyond structured fields.

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?

A single dense sentence that front-loads the output (median price and range) before the methodology. Every clause earns its place, though the parenthetical threshold could be tightened.

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?

No output schema, so the description correctly names what is returned (median + range), but leaves units/currency, output shape, and the no-data case implicit. Combined with zero parameter documentation, an agent can pick this tool but not confidently call it.

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 burden. 'Por modelo e capacidade' maps to the two parameters but gives no format, allowed values, or examples (e.g. 'iPhone 13' vs '13', '128GB' vs '128'), so an agent cannot reliably format a call from this text.

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?

States a specific resource and computation: median price and price range for used iPhones segmented by model and capacity. It is clear what the tool returns, though it never names how it differs from siblings like detalhes_aparelho or buscar_iphones, which plausibly also expose pricing.

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?

No explicit when-to-use or when-not guidance, and no alternative tool is referenced. The agent must infer from the returned metric (a market reference, not a listing) that this differs from search/detail siblings, which is a real risk given the sibling set.

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