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

Annotations already declare readOnly, idempotent, non-destructive, openWorld, so the safety profile is covered. The description adds genuinely useful behavioral context beyond that: weekly rather than daily data, ARS per live kilogram, SIO as the source, and a low-data warning threshold of fewer than 200 head per category. It does not discuss latency, auth, or pagination, but those are low-relevance for a public read-only price endpoint.

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?

The definition is front-loaded with the core purpose, then exclusions, then parameter behavior, which is the right order. It is dense and somewhat telegraphic (SIO, ARS/kg vivo, cab) and the bilingual duplication adds length, though that duplication genuinely helps an English-speaking agent parse an otherwise Spanish-only definition.

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?

A single optional parameter read tool with an output schema and safety annotations needs exactly this: what data is returned, at what cadence, in what units, from what source, with what caveat about thin categories, and which siblings it must not be confused with. Nothing an agent needs in order to call it correctly is missing.

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 0%, so the description must carry semantics. It identifies 'categoria' as an enum that filters to a single category and states that omitting it returns all categories, which is the key invocation behavior. The enum values themselves are already in the schema, so the description does not need to repeat them, but its first-sentence listing reinforces them in human terms.

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?

The description names a specific resource (Argentine cattle prices by category from the Mercado Agroganadero), the unit (ARS/kg live), the cadence (weekly SIO observation), and the exact categories covered. It also names the siblings it is NOT (cattle_price_index for daily INMAG, livestock_prices_detailed for subcategories), so an agent can route without opening schemas.

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?

Explicit when-not guidance is present: 'NO es el INMAG diario (cattle_price_index, no comparar 1:1) ni subcategorías (livestock_prices_detailed)'. The default behavior ('sin arg, todas') and the filter behavior ('categoria (enum) filtra una') are both stated, leaving no inference needed about when to call this versus its alternatives.

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