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

Annotations already declare readOnlyHint=true, destructiveHint=false, openWorldHint=true, and idempotentHint=false. The description adds important behavioral context beyond annotations: pricing, failed-call policy, auth options, and the fact that repeated calls are charged.

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?

The purpose is front-loaded and most sentences carry useful information. The first sentence is dense with output-field details, but the overall structure remains efficient and readable.

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, so the description needs to explain return values, and it does: nearest populated place, largest place within radius, country/ISO code, administrative region, population, distance, Wikidata id, and nearby places. It also covers pricing and auth, making the definition complete enough for an agent to call correctly.

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%, so lat, lon, and radius are already documented in the schema. The description provides an example coordinate pair and mentions radius indirectly, but adds little parameter semantics 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?

The description states a specific verb and resource: turning latitude/longitude into place names. It distinguishes itself from the sibling geocode by explicitly saying to use geocode for place name to coordinates, and it names the key returned geographic fields.

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 concrete use cases such as labeling GPS points, photos, deliveries, or IP-derived coordinates. It also explicitly routes the opposite operation to the sibling tool geocode.

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