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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds genuinely new context: the auth requirement (client must be logged in) and the data-minimization scope (only the first name is returned), which the agent needs to reason about failures and privacy.

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?

Three short sentences: capability first, then usage, then prerequisite. Every sentence earns its place with zero padding or repetition of the title.

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 zero-required-param read tool with no output schema, the description supplies the missing return-shape information ('nombre de pila' and 'desde cuándo') and the login prerequisite. Only the country/store dimension is left unexplained, which is minor since the schema documents 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 single 'country' enum parameter is fully documented in the schema, so the description carries no burden here. However, the description never mentions that store selection (es/fr) affects language, prices and links, adding nothing beyond the schema. 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?

States a specific verb and resource ('comprueba qué cuenta de Zacatrus tiene conectada') plus the exact payload scope ('solo el nombre de pila') and 'desde cuándo'. This clearly separates it from account-adjacent siblings like my_orders, my_box, or my_club, which return different data.

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?

Explicitly names two use cases ('saludar al cliente', 'comprobar que la conexión funciona') and states the prerequisite that the client must be logged in. It does not name alternatives or when-not-to-use, but the sibling set is disjoint enough that this is a minor gap.

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