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

No annotations are provided, so the description carries the full behavioral burden. It does add one genuinely useful behavioral fact beyond the schema — a metered, wallet-authenticated payment model ('5 free trial calls per signed wallet') — but it omits anything about supported unit set, error handling, or return format for a tool with three undocumented parameters.

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?

Two sentences, front-loaded with the core purpose, with no wasted preamble. The emoji-laden pricing sentence is slightly promotional in tone but short enough not to bloat the definition.

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?

With no annotations, no output schema, and three parameters at 0% schema coverage, the description should specify accepted units and the value format, and it does neither. An agent knows the general intent but lacks what it needs to construct a valid call.

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 0%, so the description must compensate for all three parameters, and it does not: 'from', 'to', and 'value' get no explanation. The names are suggestive, but 'value' is typed as a string with no stated format (numeric string? unit suffix?), and accepted unit tokens for 'from'/'to' are never listed.

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 gives a specific verb and resource: 'Convert between weight units.' An agent can tell this is a unit-conversion tool without opening the schema. However, it does not differentiate from the many sibling converters (x402-units-convert, x402-metric-imperial, x402-kg-to-pounds, x402-grams-to-ounces), leaving ambiguity about when this generic converter beats the dedicated ones.

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 which units are supported, and no exclusions naming alternative conversion tools. The only extra context is a promotional note about free trial calls, which does not help an agent choose between this and sibling converters.

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