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

No annotations are supplied, so the description carries the full burden. It does add genuinely useful behavioral context the schema cannot convey: the tool is paid and metered at 5 free trial calls per signed wallet, implying wallet signing and a cost after the trial. It omits units (newtons vs pounds), expected numeric format, and precision, which matter for a physics calculation.

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?

Three short sentences with the definition and formula front-loaded ahead of the parameter prompt. The promotional line about free trial calls is filler but brief and does convey pricing behavior.

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 arithmetic tool with no output schema, the description covers the operation adequately, but with zero schema descriptions and no annotations, missing unit conventions and the response shape (number, units, string) leave real gaps an agent would want closed.

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 coverage is 0% for both parameters and neither is marked required, so the description must explain them. It names mass and acceleration and ties them to the formula, but never states units, accepted string formats (plain decimals vs expression strings), ranges, or whether negative values are meaningful, leaving the typing of these string params unexplained.

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?

States a specific verb and resource and even gives the formula (force = mass × acceleration), so the computation is unambiguous. It does not distinguish itself from closely-named siblings such as x402-centripetal-force, x402-gravitational-force, or x402-impulse, which are also force computations.

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?

'Provide mass and acceleration values' gives a minimal hint about what to supply, but there is no statement of when to pick this over the centripetal/gravitational force siblings, no prerequisite list, and no exclusion conditions. Usage is only implied.

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