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 earns credit beyond that by disclosing the return shape (series identifier, ámbito, unit, frequency, source, and last price with date), which is essential given there is no output schema. It omits result-limit behavior and empty-result handling.

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 dense sentences, zero filler. The core search scope is front-loaded and the return contract follows immediately, with examples embedded inline rather than padded into a separate list.

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 4-parameter read tool with no output schema, the description covers the searchable dimensions and the returned fields, which is the bulk of what an agent needs. Remaining gaps are minor: no statement about the default/max result limit or what an empty match returns.

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 the baseline is 3, but the description adds real meaning: the example strings show what free text 'texto' accepts, and the phrase 'producto, variedad o provincia' plus the 'gasóleo zaragoza' example maps the free text onto the separate 'ambito' dimension. 'fuente' and 'limite' are left entirely to 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?

States a specific verb and resource ('Busca series de precios por producto, variedad o provincia') and reinforces it with four concrete query examples, so the agent knows exactly what corpus is searched. It does not, however, contrast itself with siblings like precio_ultimo or historico, which also return price data, leaving overlap to inference.

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 only implied: the example queries ('naranja navelina', 'gasóleo zaragoza') show the shape of a valid lookup but the description never says when to pick this tool over precio_ultimo, historico or gasoleo_hoy, nor when it is the wrong choice. Adequate for a simple search tool, but no explicit routing guidance.

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