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

Annotations already declare readOnlyHint and idempotentHint, so safety is covered. The description adds genuinely useful behavior beyond that: the data source is the latest monthly report, and it is supplemented with live 'abierto ahora mismo' figures, which tells the agent about data freshness and the mixed vintage of the numbers.

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?

It is a single dense sentence, front-loaded with the source and scope, then the metric list, and closes with the live-data caveat. It is slightly run-on laundry-list prose, but every clause maps to a real returned figure and nothing is padding.

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 one optional parameter, no output schema, and annotations covering the safety profile, the description carries the remaining burden well by enumerating essentially every metric the report returns. An agent knows what it will get and how scope works before calling 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 100% and the provincia parameter is already documented as falling back to all of Spain. The description restates the same Spain-or-province scoping without adding format, casing, or matching rules 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 resource and verb: aggregate figures from the latest monthly Piso Radar report, scoped to Spain or one province, and enumerates the metrics returned (open auctions, discount, occupancy, liens, deposits, bank flats, price/€/m², top entities). It is clearly an aggregate-report tool rather than a listing search like buscar_viviendas or a detail lookup like ficha_vivienda, though it never names those siblings explicitly.

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 by the content: it says it covers 'toda España o una provincia' and mixes monthly report data with what is open right now, which hints at when to reach for it. However, there is no explicit statement of when to use it instead of buscar_viviendas or subastas_que_cierran, nor any exclusions, so the agent must infer the routing.

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