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 meaningful behavior beyond that: it discloses exactly what a hit contains (identifier, ámbito, unidad, frecuencia, fuente, último precio con fecha), which matters since there is no output schema.

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 sentences, zero filler: the search capability and its examples come first, the return shape second. Every clause carries information an agent can act on.

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, describing the returned fields is exactly the right compensation and it is done well. The gaps are minor: how 'texto' interacts with ámbito/fuente filters and the role of the limite default (10, max 20) are left to the schema alone.

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 75%, so most parameters are already documented in the schema. The description's four example queries usefully illustrate what 'texto' accepts (including a combined product+province query) but adds nothing about ambito, fuente or the limite cap.

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 ('Busca series de precios') and enumerates the dimensions searched (producto, variedad, provincia) with four concrete example queries. The return statement about identifiers distinguishes it from siblings like precio_ultimo, but no sibling is named explicitly, so it stops short of a 5.

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 examples ('naranja navelina', 'gasóleo zaragoza') and by the fact that it returns series identifiers for later lookup. There is no explicit statement of when to use this versus precio_ultimo or historico, and no exclusions or prerequisites are given.

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