Adjuntar archivo a factura

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

The sole annotation readOnlyHint=false already signals a mutation, so credit here comes from added context: the write-enablement prerequisite and the accepted file formats (PDF or image). It remains silent on whether re-attaching overwrites a prior file, size limits, and what the call returns, which are meaningful gaps for a write operation.

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?

Two short sentences, front-loaded with the action and the file-type constraint, followed by the permission prerequisite. No filler and nothing redundant with the schema.

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 four-required-parameter mutation with no output schema, the description covers the target, the accepted inputs, and the write-enablement prerequisite. The remaining gap is return/overwrite behavior, which is moderate rather than critical given the tool's narrow scope.

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 50%, with descriptions present only for periodo and rutaArchivo. The description partially compensates by explaining that the target is a received or issued invoice, which maps onto the undocumented 'tipo' enum, but it adds nothing about 'invoiceId' or about format expectations for the file path beyond the schema text.

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 gives a concrete verb and resource: 'Adjunta un archivo local (PDF o imagen de la factura) a una factura recibida o emitida', including accepted file types and the two invoice kinds. That is specific enough to distinguish it from the reverse-direction sibling cs_download_invoice_pdf, though it never names that sibling explicitly.

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?

'Requiere escritura activada' is a clear prerequisite for use, and the file-type scope implies when the tool applies. However, there is no explicit when-not guidance (e.g. what to do if the invoice has no PDF yet, or whether this replaces an existing attachment), leaving usage partly inferred.

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