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

No annotations are supplied, so the description carries the full behavioral burden. It discloses the payment/trial model (5 free calls per signed wallet), which is genuinely useful context, but says nothing about expected input units, the constant or formula applied, rounding, error handling, or response shape for a computation tool with three untyped-looking string parameters.

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?

It is short and front-loaded, so there is no padding to trim, but the second half is marketing copy about free trial calls rather than tool semantics. The space freed by the terse wording is not spent on the information an agent actually needs.

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 three-parameter scientific calculator with no annotations, no parameter descriptions, and no output schema, the description is materially incomplete: an agent cannot know what units to pass or what value comes back. Only the trial/payment note exceeds what structured fields already provide.

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 for three undocumented parameters, and it does not. It never references mass1, mass2, or distance, nor their units (kg, meters) or why they are declared as strings; the physics domain only weakly implies their meaning.

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?

"Gravitational Force: Force of gravitational" restates the tool name in circular form rather than stating a specific action such as "compute the gravitational attraction between two masses." An agent can infer the domain from the name, but the description adds no verb, no formula, and no output meaning, and it does nothing to distinguish this from near-siblings like x402-force, x402-gravitational-constant, or x402-earth-gravity.

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 guidance, no preconditions, and no mention of any alternative tool. The only auxiliary information is a pricing note about free trial calls, which does not help an agent decide when this tool is the right choice over the many adjacent physics/force 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.