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

There are no annotations to indicate read-only behavior, destructive potential, or idempotency. The description only restates the purpose and adds no behavioral context such as whether conversion is synchronous, whether it accepts multiple formats, how errors are handled, or what output shape to expect. For a conversion utility with no annotations, the description carries the burden of behavioral disclosure but fails to meet it.

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 and front-loaded, which is appropriate for a simple utility. It states the action and resource in one sentence without filler. However, it is so minimal that it misses opportunities to mention supported units or invocation details, so it isn't a perfect 5.

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 the absence of an output schema, annotations, and parameters, the description should explain what the tool returns and how to invoke it. It does neither. An agent knows only that acceleration units can be converted, but has no idea what inputs to provide or what output format to expect. This is incomplete for a usable tool definition.

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?

The input schema is an empty object with no parameters, so schema coverage is 100% but there is nothing to document. The description at least clarifies the tool's domain (acceleration units), which is the only meaningful semantic an agent needs since no parameters are exposed. With zero parameters, the baseline is 4, and the description does not detract.

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 states a clear verb and resource: 'Convert between acceleration units.' This communicates the tool's function as a unit conversion utility. The name x402-acceleration also reinforces the resource, but the description adds the action, which is specific enough to distinguish it from generic math or physics tools among the many siblings.

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?

The description offers no guidance on when to use this tool versus alternatives like x402-velocity, x402-force-unit, x402-speed-convert, or x402-units-convert. It doesn't specify supported units, input formats, or whether it handles single values or arrays. Without this, an agent cannot confidently choose it over the many similar conversion tools in the sibling list.

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