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

Annotations already declare readOnly, openWorld, idempotent, and non-destructive behavior. The description adds valuable context beyond those: the upstream providers (Nominatim / BigDataCloud), the per-call cost, and the HTTP GET endpoint. It does not contradict any annotation.

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 description is extremely compact and front-loaded: purpose first, then source, cost, and endpoint. Every clause contributes information without filler, making it easy for an agent to parse quickly.

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, read-only geocoding tool with rich annotations and full schema coverage, the description is nearly complete. It lacks explicit output-format details, but no output schema exists and the phrase 'nearest address' conveys the expected result. Minor gaps like error handling or no-result behavior prevent a 5.

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 examples and descriptions for both lat and lon. The tool description itself does not add extra parameter-level meaning, but it does not need to because the schema already documents the parameters fully. Baseline 3 applies.

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 transformation ('Coordinates → nearest address') and reinforces it with the 'Reverse geocoding' label. This clearly differentiates from sibling v1_geocode and other tools without ambiguity.

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 clearly communicates the direction of the tool (coordinates in, address out), which tells an agent when to use it versus the likely forward-geocoding sibling. It does not explicitly name alternatives or exclusions, but the context is unambiguous for the main use case.

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