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

No annotations are provided, so the description must carry the full burden of explaining behavior. It does not disclose whether the tool expects decimal degrees, whether the haversine formula is used, whether this is a read-only computation, or what the output looks like. For a distance calculation tool, the lack of unit/accuracy details is a meaningful 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?

The description is extremely short, so it is not bloated, but it is under-specified rather than concisely complete. The phrase 'Distance between geo' is mostly redundant with the tool name 'x402-geo-distance' and adds almost no new information.

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?

Given 8 parameters, no annotations, no output schema, and a vague description, the tool is not adequately documented. An agent would struggle to know whether to supply lat1/lon1 and lat2/lon2, or fromLat/fromLon and toLat/toLon, or all four pairs, or what units the result will use.

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% but every parameter description is the unhelpful placeholder 'X to process'. The description provides no extra meaning about which parameters represent a point pair, which ones are from/to, or how the four coordinate values combine. With 8 string-typed parameters and zero meaning added by the description and schema, an agent cannot reliably know it needs exactly four coordinates and should pass one point's lat/lon and another point's lat/lon.

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 'Geo Distance: Distance between geo' is a near-tautology that simply restates the tool name in slightly different words. It identifies that the tool computes distance between geographic points, but gives no detail about what kind of distance (great-circle, Euclidean, haversine, driving?) or which coordinate formats are accepted.

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?

There is no guidance on when to use this tool versus alternatives such as x402-distance, x402-distance2d, x402-manhattan-distance, or x402-great-circle-distance. The description does not explain the specific geographic use case, units returned, or whether it is appropriate for address-based distances.

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