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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world. The description adds genuinely non-redundant context: the tool is public with no account required (auth/permission info) and it discloses a scope limitation (no market/pricing data). What it omits beyond that is minor for a read-only stats call.

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 with no filler; the scope/content comes first and the exclusions and public-access note follow. Slightly compressed but every clause carries information.

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 an output schema present, return-value detail is unnecessary, and the description supplies the access model, the content scope, and the Pro-feature exclusion. For a 2-param tool with full schema coverage and existing annotations, it is essentially complete, missing only an explicit named alternative.

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 the baseline is 3, but the description adds real meaning: it warns that property-type filters must use EXACT values and documents the municipality key format (`provincia:municipio`) for municipio_q, which is not evident from the param name alone.

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 concretely enumerates what the tool returns (catalog totals, provinces with active/historical auctions, property types, municipality search) and explicitly carves itself apart from the market-statistics tool by stating prices and award rates are a Pro feature. An agent can distinguish this from siblings like mercado or buscar_subastas without opening a schema.

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?

It gives clear context for use ('Pública, sin cuenta') and a strong when-not signal ('No incluye estadísticas de mercado ... plan Pro'), which implicitly routes market queries elsewhere. It does not name a specific alternative tool, so it falls just short of the explicit alternatives a 5 requires.

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