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

With no annotations, the description carries the full burden of behavioral disclosure and provides none: no error behavior, no statement of whether values/weights must be equal length, no rounding or output format information. The pricing line describes billing, not tool behavior.

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, but the space is wasted: the first clause is tautological and the second is unrelated marketing copy. Nothing is front-loaded that helps an agent act.

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 computation tool with no annotations, no output schema, and zero schema coverage, the description supplies essentially none of the missing context. An agent would have to guess the input serialization to use it at all.

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% and both parameters are typed only as bare strings. The description adds no meaning about delimiter format, number format, or whether the two lists must match in length, leaving the agent unable to form a valid call.

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?

"Average of weighted" merely restates the tool name and never says what kind of weighted average is computed or what the two inputs represent. It does not distinguish this from siblings such as x402-weighted-mean or x402-weighted-median, so an agent cannot reliably choose it.

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?

No when-to-use, when-not-to-use, or alternative guidance is given. The only extra sentence is a pricing note about free trial calls, which says nothing about selecting this tool over its many statistical siblings.

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