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

No annotations are supplied, so the description carries the full burden of behavioral disclosure, and it discloses nothing: no mention of input format, numeric coercion, output shape, or error behavior. The four string parameters strongly suggest numeric inputs but the description never confirms or explains this.

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?

Only four words, but this is under-specification rather than conciseness — the name is repeated with a colon and no additional content. Brevity here costs information rather than saving tokens.

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 4-parameter computation with no annotations and no output schema, the description supplies none of the needed context: not the operation's mathematical definition, not the expected numeric inputs despite all parameters being typed as strings, and not the return shape.

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 nominally 100%, so the baseline of 3 applies. However, the schema texts are pure placeholders ('Ax to process', 'Bx to process') that convey no real semantics about types, expected numeric values, or which pair is vector A versus B; the description contributes nothing to compensate, leaving the score at the baseline floor rather than higher.

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 is 'Cross Product2d: Cross Product2d' — a pure restatement of the tool name with no verb, resource, or scope added. An agent learns nothing beyond what the name already says, and no distinction from the many sibling math utilities is offered.

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 indication of when to use this tool, what inputs it expects, or which alternatives (e.g. x402-vector-cross, x402-distance2d) exist. Nothing is provided to route the agent.

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