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

With no annotations the description carries the full burden and does so: it discloses the cost model ('free when there are no enclosures'), the error path (SIG_001, nothing charged, retry in a few seconds), the call count ('one API call'), and the attribution obligation ('cite Fuente: FEGA - SIGPAC'). That is unusually rich operational context for a read tool.

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 with the resource and its returned fields, then operational constraints. The long field enumeration is information-dense rather than filler, though it could be broken up for readability.

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?

There is no output schema, and the description compensates by enumerating return fields, explaining the `match` flag, coverage limits, and failure behavior. An agent has everything needed to call it and interpret the result.

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 baseline would be 3, but the description adds value beyond the schema: it explains that land-use names are localized to the requested language, that include_geometry returns a 'large' GeoJSON outline, and it documents the 'match' output semantics. `country` and `reference` add nothing beyond the schema.

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 ('every SIGPAC enclosure (recinto) of a Spanish parcel') and enumerates the returned fields precisely, so the agent knows exactly what it gets. It does not name siblings like get_parcel or get_parcel_subparcels, so the boundary with those tools is inferred rather than stated.

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 a clear when-not condition ('Spain, the Basque Country and Navarre only; other countries answer CNV_COVERAGE') and a conditional for include_geometry, which is useful routing context. However, it never says when to pick this over get_parcel or get_parcel_subparcels, leaving the main sibling choice to inference.

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