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

With no annotations provided, the description carries the responsibility for behavioral disclosure. It does mention the pay-per-use cost (x402: 0.004 USDC) and clarifies that the input is free text, which is useful. However, it doesn't disclose potential failure behaviors, whether output is a raw JSON result or a wrapper, or any constraints on input length or content.

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 to-the-point, with the core action stated first and the parameter and cost notes appended. It has no irrelevant filler, though the inline 'input=text' is slightly informal compared to a structured explanation. Overall, it is easy to read and quick to parse.

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 tool with one parameter and no output schema, the description covers the essential basics: what it does, what the input is, and that it costs money. However, it lacks guidance on when to pick this tool over its many siblings and doesn't describe the shape or container of the returned JSON. Given the absence of annotations, a bit more context would help an agent confidently select and invoke it.

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 schema fully covers the single parameter 'input' with a description ('texto del que extraer datos'). The description adds only 'input=text', which is redundant and lacks extra context such as an example or specific formatting. Because schema coverage is 100%, the description doesn't need to do much, but it also adds little value beyond the schema.

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 clearly states the tool's function: 'Extract structured data from free text and return it as JSON.' This specifies a distinct verb and resource with a concrete output format. It is not explicitly differentiated from sibling tools, and there is no note about when to prefer it over json-fix or other extractive tools, but the core purpose is unambiguous.

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 guidance is given about when to use this tool compared to alternatives like json-fix, entities, or ai-inference. The description simply states the action and mentions the input field; it does not provide exclusionary criteria or example scenarios, leaving the agent to infer the appropriate context.

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