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

Annotations already cover the read-only/idempotent/closed-world profile, yet the description adds real value: it discloses per-source cadence and start dates, and the truncation rule (returns the most recent points when exceeding max_puntos, full series in the linked CSV). The truncation behavior is exactly the kind of result-shaping detail an agent needs.

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, purpose front-loaded, and the long parenthetical carries only substantive data-coverage detail. Dense but every clause earns its place.

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, the description adequately explains what is returned (a price series, truncated to max_puntos, with the full series available via CSV). Combined with annotations this is complete enough to call the tool correctly.

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%, and the description compensates for the undocumented max_puntos by explaining its default (104), cap (520) and recency behavior, plus the date-range meaning of desde/hasta. It adds meaning beyond the raw schema constraints.

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+resource: returns the price series of an identifier between two dates. The date-range scope implicitly separates it from siblings like precio_ultimo and gasoleo_hoy, 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?

The parenthetical documents per-source data coverage and cadence (weekly from 2017 in Comunitat Valenciana, etc.), which helps judge fit, but there is no explicit when-to-use guidance or comparison against precio_ultimo/gasoleo_hoy/plazos. Usage is left to inference.

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