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

No annotations are provided, so the description must carry behavioral context. It discloses the payment mechanism ('x402: 0.003 USDC on Base, pay-per-use'), which is useful, but omits other traits like rate limits, authentication needs, or error handling for invalid URLs.

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 extremely concise, consisting of two short sentences that are front-loaded with the core functionality and then the input requirement and payment note. Every sentence earns its place.

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 basics: action, input, and return. However, given the absence of annotations, it could do more to explain output format (e.g., plain text extraction) or limitations (e.g., URL must be publicly accessible).

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 100%, meaning the parameter 'input' is fully described in the schema as 'service input'. However, the description adds a crucial semantic detail: that the input should be a PDF URL, which the schema description lacks.

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 ('Descarga') and resource ('PDF por URL'), and clarifies the return value ('devuelve su texto'). This clearly distinguishes it from siblings like 'read-pdf' (which likely reads local files) by emphasizing URL download.

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?

Usage context is implied by the URL requirement, and the pay-per-use note hints at a cost, but there are no explicit when-to-use (or when-not-to-use) guidelines or alternative tools mentioned (e.g., local file readers).

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