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

Annotations already convey read-only, idempotent, open-world, non-destructive. The description adds 'no auth required' and identifies the official data source, which is useful operational context. It does not discuss error behavior for coordinates outside Argentina, but with an output schema present this is a minor gap.

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 sentences, front-loaded with the action and output, then the data source and auth detail. No filler words; each clause earns its place.

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 two-parameter reverse geocoder with an output schema, the description covers the operation, scope, and useful operational details (auth, source). It doesn't specify behavior for out-of-bounds coordinates, but the 'within Argentina' phrasing implies the expected domain, making it adequately complete.

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 100%, with both lat and lon fully described including decimal degrees and ranges. The description merely calls them a 'lat/lon coordinate pair' and adds no meaning beyond the schema, so the baseline 3 is appropriate.

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 states a specific operation: reverse geocoding a lat/lon pair, and names the output resource (administrative location: province, department, municipality) and the geographic scope (Argentina). It is clearly distinct from forward geocoding (indec-georef.location.geocode) and from other country geocoders by naming the data source.

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 description gives clear context: it takes a lat/lon pair and returns administrative divisions, and specifies the 'within Argentina' condition. It does not explicitly name when-not to use it or point to alternatives such as the forward geocoder or other reverse geocoders, so it falls short of full 5.

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