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

No annotations are supplied, so the description carries the entire behavioral burden. It does disclose the payment/auth model ("5 free trial calls per signed wallet"), which is genuine context, but says nothing about the conversion base (1000 vs 1024), rounding, accepted input format, or error behavior for malformed values.

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 short sentences, front-loaded with the operation, with the free-trial note trailing. Nothing is padded, though the marketing emoji adds no informational value.

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 trivial single-value converter this could be adequate, but the ambiguous two-parameter schema with no required fields and no descriptions is exactly what the description needed to resolve, and it does not. Combined with absent annotations and no output schema, the definition is under-specified for correct invocation.

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% and there are two undocumented string parameters, "gb" and "value", neither required. The description does not explain what each represents, which one takes the amount, or why both exist, so the agent has no basis for choosing between them.

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?

"Convert gb to mb" names the operation and the direction, so there is no doubt what it computes. But the sentence is essentially the title restated, and it never distinguishes this from the obvious sibling x402-mb-to-gb or the generic x402-units-convert, leaving the agent to infer selection from the name alone.

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 reach for this versus x402-mb-to-gb, x402-data-size, or x402-units-convert, nor any precondition for using it. The only usage-adjacent sentence concerns the free trial quota, not task selection.

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