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. It does reveal the core computation (division of distance by time), which is the essential behavior. However, it omits unit conventions, output format, error handling for zero time, and whether results are rounded or returned as raw numbers—gaps an agent cannot fill from structured data since both annotations and output schema are absent.

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?

The description is compact and front-loads the formula in the first sentence, which is good. But it contains redundancy—'Velocity: Calculate velocity:' repeats the tool name as both prefix and verb—and the second sentence could have been folded in more economically.

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-variable calculation, the formula and required inputs are both stated, which is the minimum viable content. But completeness suffers from the empty input schema, unspecified units, and no mention of edge cases or return format, so an agent still has meaningful ambiguity about invocation.

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 is empty (zero properties), so the description's mention of 'distance and time values' adds meaning the schema cannot convey, which earns credit. However, the instruction is vague about types, units, and format, and there is a structural mismatch: the schema declares no parameters while the description requires two inputs, leaving the agent unsure how to actually pass them.

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 states a specific verb and resource ('Calculate velocity') plus the defining formula ('distance divided by time'), making the tool's function immediately identifiable. It implicitly differentiates from siblings like x402-acceleration (which would be velocity over time) and x402-angular-velocity, though it does not explicitly distinguish itself from the closely related x402-speed, which shares the same distance/time formula.

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 guidance on when to use this tool versus alternatives such as x402-speed, x402-acceleration, x402-wave-speed, or x402-velocity-related calculators. The instruction 'Provide distance and time values' addresses inputs, not usage context or exclusions, leaving an agent to guess which tool fits a given request among the many similar physics calculators.

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