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

With no annotations, the description carries the full burden. It does disclose one genuinely useful behavioral fact — 5 free trial calls per signed wallet, implying a paid/auth-gated endpoint — but says nothing about return format, rounding or precision, or what happens after quota is exhausted.

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 sentence is short and front-loaded with the operation, which is good, but the bulk of the text is a promotional trial-call banner rather than tool semantics, so little of the space is spent on things that help invocation.

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 two-parameter conversion tool with no annotations, no output schema, and zero schema coverage, the description should at minimum explain the two inputs and the result shape. It resolves none of that, leaving the caller unable to fill the schema confidently.

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 neither of the two string parameters is documented anywhere. The description implies 'mb' is the megabyte input but never mentions the second parameter 'value', leaving an agent to guess how the two relate or which to fill.

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 mb to gb" gives a verb and a resource direction, so the basic operation is inferable, but it is essentially a restatement of the tool name and offers nothing to separate it from near-identical siblings such as x402-gb-to-mb, x402-units-convert, or x402-data-size.

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 statement of when to use this versus the reverse converter or the generic unit-conversion tools, and no prerequisites or exclusions. The only usage-adjacent text is a free-trial quota, which is about payment, not about when the tool applies.

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