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

Annotations already declare readOnlyHint, idempotentHint, and openWorldHint=false, so the safety profile is covered. The description adds useful value by explaining what each result contains ('what happens that day and its official source'), clarifying the returned content beyond the annotations.

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?

Front-loaded and efficient, giving the purpose in the first clause. The Spanish sentence largely restates the English one, adding mild redundancy, though it may serve a bilingual audience.

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 simple read-only, zero-required-param tool with no output schema, the description covers what it does and what a result includes. Nothing critical to correct invocation is missing, given the fully documented schema.

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 100%, so both params (tema, desde) are fully documented in the schema. The description's mention of CAP and taxes echoes the tema enum values but adds no syntax or semantics beyond what the schema already provides; 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 resource (upcoming official dates) with scope (farmers in Spain) and concrete examples (CAP, quarterly taxes). It is clearly distinguishable from the price-oriented siblings (gasoleo_hoy, precio_ultimo, historico), which handle a different domain.

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 purpose implies when to use it (looking up upcoming agricultural/official deadlines), but the description gives no explicit when-to-use guidance, exclusions, or comparison to alternatives. Usage must be inferred from the topic.

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