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

With no annotations, the description carries the full burden. It usefully discloses the payment model (x402, 0.02 USDC on Base, pay-per-use), which is real behavioral context an agent needs. However it says nothing about output shape, minimum row/column requirements, or failure modes for non-numeric or malformed CSV.

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 compact clauses front-load the purpose, then input format, then cost. Nothing is wasted, though the bracketed pricing token is slightly dense relative to the otherwise terse phrasing.

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 one-parameter tool with no output schema, the essentials are present: what it computes, what it accepts, and what it costs. It stops short of describing the returned matrix or any size constraints, but the low complexity keeps this from being a serious gap.

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 nominally 100%, but the schema description for the single parameter is only the generic 'service input'. The description compensates by stating 'input=URL o CSV crudo', which clarifies the accepted source formats beyond the schema. Baseline 3 is exceeded because this is genuine added meaning.

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+resource: 'Matriz de correlación de un CSV' is unambiguous about the computed artifact and the input type. It does not, however, distinguish itself from near-neighbors like estadisticas-descriptivas or detectar-outliers in the sibling list.

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 guidance, no prerequisites, and no named alternative among the many analytics siblings (estadisticas-descriptivas, detectar-outliers, pivotar-datos). The agent must infer usage entirely from the purpose phrase.

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