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

Annotations already declare readOnly/idempotent/non-destructive, so safety is covered. The description adds useful behavior the annotations don't: data freshness ('último día hábil'), units (ARS/kg vivo), and the payload shape (min/avg/max plus head count). It stops short of rate limits or caching behavior, so not a 5.

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?

Dense but front-loaded: purpose, then the disambiguating comparisons, then the parameter note, then an English gloss. Uses compressed notation, but every clause carries information; slightly long for a one-parameter read tool.

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?

No output schema exists, so the description carries the return-value burden — and it does, specifying min/avg/max, units, live-weight basis, and head counts, plus the optional filter. Nothing needed to call this 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 coverage is 0%, but the single enum parameter is fully explained: the description lists the grupo values and defines the no-filter default ('sin filtro, todas'), which the schema does not state. Adds real meaning about default behavior beyond the enum list.

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 (precios por SUBCATEGORÍA del Mercado Agroganadero) with concrete example categories ('NOVILLOS Regular +430'), the returned measures (mín/prom/máx en ARS/kg vivo + cabezas) and the data recency (último día hábil). It also explicitly names the siblings it is not (livestock_prices, cattle_price_index), so an agent can disambiguate 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?

Gives the exact selection rule against both nearest alternatives: more granular than livestock_prices (categorías), and explicitly NOT the daily INMAG index (cattle_price_index). Both when-to-use and when-not-to-use are stated.

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