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

With no annotations, the description carries the full burden, and it does disclose one behavioral trait beyond the schema: the free-trial/payment model ('5 free trial calls per signed wallet'), implying wallet-based auth. It says nothing about determinism, unit handling, or behavior on malformed/non-numeric input.

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?

One compact sentence with the core operation front-loaded, followed by the pricing note. Nothing is wasted, though the emoji-marked trial clause is promotional rather than functional.

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-input arithmetic tool with no annotations and no output schema, the description covers the operation but omits units, input format expectations, and any statement of the returned value's shape or precision. Adequate to attempt a call, but not complete.

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; it names both parameters implicitly through the formula current x resistance. However, the parameters are typed as strings with no format guidance, and the description never states expected units (amperes, ohms) or whether decimals/scientific notation are accepted, leaving a real gap.

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?

Names a specific verb and result ('Computes voltage') plus the exact relationship ('current times resistance'), which cleanly separates it from the sibling x402-ohms-law-i and x402-ohms-law-r variants. It does not explicitly name those siblings, so an agent must infer the family distinction from the 'V' suffix.

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 or when-not-to-use guidance and no alternatives are mentioned, so the agent is left to infer that this is the voltage variant of a three-part Ohm's law family. For a simple calculator that inference is easy, but nothing in the text supplies it.

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