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

With no annotations provided, the description carries the full burden of behavioral disclosure and says nothing — no mention of what the tool computes, whether it is read-only, what it returns, or any constraints. 'Power of unit' is meaningless as behavioral context.

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?

At six words the description is short, but this is under-specification rather than conciseness — 'Power of unit' is a circular fragment carrying no information. There is no substance to front-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?

Even for a zero-parameter utility, the description is completely opaque. An agent cannot determine what the tool computes, what output to expect, or how it differs from x402-power or x402-force-unit, and no output schema or annotations compensate.

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 has zero parameters, so there is nothing the description needs to clarify about arguments. Per the zero-parameter baseline of 4, the empty schema is not a gap, though the description itself contributes nothing.

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 'Power Unit: Power of unit.' is a tautology — it restates the tool's name without a verb or action. An agent cannot tell whether this tool converts power units, calculates electrical power, or raises a value to an exponent, and nothing distinguishes it from siblings like x402-power, x402-force-unit, and x402-units-convert.

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 zero guidance on when to invoke this tool versus any of the thousands of x402 siblings. No context, prerequisites, or exclusions are provided, leaving the agent to guess at routing.

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