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

With no annotations, the description carries the full behavioral burden; it discloses the deterministic formula and adds the commercial detail '5 free trial calls per signed wallet', which tells the agent about auth/billing. It does not state units, expected input format, or what happens with invalid or missing values.

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, front-loaded with the purpose and formula. The emoji trial-call sentence is promotional but also carries auth/billing information, so it roughly earns its place.

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 simple two-parameter calculator with no output schema, the formula plus parameter roles are mostly sufficient, but the absence of unit conventions means an agent cannot reliably predict the result's units or validate its own inputs.

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 fully explain the two parameters. It clarifies that 'distance' is the lever arm and that the two are multiplied, but both params are typed as strings and the description never says whether to pass bare numbers or values with units (e.g. '10' vs '10 N'), leaving a significant ambiguity.

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 resource ('Calculate torque in physics') and even states the formula 'force multiplied by distance (lever arm)', which differentiates it from neighbors like x402-force, x402-distance, and x402-work without opening a schema.

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 named alternative. 'Provide force and distance values' is an input hint, not usage guidance, so the agent must infer that this is the right tool for a moment-of-force calculation.

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