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

No annotations are provided, so the description carries the full burden of behavioral disclosure, and it delivers nothing: no statement of the formula used, the input format (the schema types are strings, oddly), units, precision, or what is returned. A 3D distance tool with zero behavioral context is unusable without trial and error.

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?

It is short, but this is under-specification rather than conciseness: the text is a redundant name:name echo with no informational content. There is nothing front-loaded because there is nothing to load.

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 6-parameter tool with no annotations and no output schema, the description should at minimum state the computation performed and the expected input format. It omits everything, leaving the agent unable to determine units, ordering, or result shape.

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 nominally 100%, which sets the baseline at 3, and the six coordinate parameters (x1, x2, y1, y2, z1, z2) are self-evidently named even though the schema text ('X1 to process') is placeholder filler. The description adds nothing about coordinate systems, units, or whether values are strings or numbers, so it does not exceed the baseline.

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 is a tautology: 'Distance3d: Distance3d' merely restates the tool name without stating a verb, resource, or the coordinate inputs used. An agent can vaguely infer Euclidean 3D distance, but nothing is explained and nothing distinguishes it from x402-distance, x402-distance2d, x402-manhattan-distance, or x402-chebyshev-distance.

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 when-to-use guidance, no mention of alternatives among the many distance siblings, and no statement of when this tool is inappropriate. The one-word name is the only signal, which is not enough to route an agent reliably.

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