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

Annotations already declare readOnly, idempotent, non-destructive and open-world, so the safety profile is covered. The description adds the backing provider (OpenStreetMap Nominatim), which usefully signals coverage and third-party rate/accuracy characteristics, but it never states rate limits, result granularity, or what happens for null returns when no address exists.

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?

A single front-loaded sentence with zero filler: action, resource, and data source in one clause. Nothing is redundant with the annotations or the schema.

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?

Low-complexity tool with a complete input schema, rich annotations, and an output schema that explains the return value, so the description needn't cover returns. It is nearly sufficient; only the edge case of no-address-at-coordinate is unaddressed.

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% — both latitude and longitude carry WGS84 degree descriptions with valid ranges — so the schema already does the heavy lifting. The description adds nothing beyond what the schema provides, making the baseline 3 correct.

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 — find the address or place at a coordinate — which is unambiguous and clearly the inverse of the sibling 'geocode'. It stops short of naming 'geocode' as the forward counterpart, so the differentiation is inferable rather than explicit.

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?

'Find the address or place at a coordinate' implies when the tool applies, but there is no explicit guidance such as using this instead of geocode when you already have lat/lon, and no mention of accuracy limits or fallbacks for missing addresses.

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