Formulario 29 (IVA mensual)

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

Annotations already declare read-only and idempotent, so the description's added value lies in disclosing the 'last 12' default and the specific data fields returned. This goes beyond the structured metadata without contradicting it.

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 a single, well-structured sentence that front-loads the key information and provides both scope and default behavior without extraneous words.

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?

With no output schema, the description conveys the essential data content (IVA, PPM, retentions, total) and the default period behavior. It doesn't cover error handling or response structure, but for a simple read-only tool with one optional parameter, it is reasonably complete.

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 covers the 'periodo' parameter with format and default mention, but the description clarifies that omitting it returns the last 12 months. This fills in the exact default behavior, adding meaning beyond the schema's generic 'valor por defecto.'

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 identifies the tool as retrieving the monthly Form 29, listing its key components (IVA, PPM, withholdings, total payable) and explicitly stating the default behavior when no period is given. This distinguishes it from sibling tools like ordis_get_f22 by its specific form number and content.

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?

The description provides clear context: it is for monthly F29 tax returns with IVA detail. It doesn't name alternatives explicitly, but the default period behavior is a useful 'when' condition for omitting the parameter. No exclusions are stated, so it earns a 4 rather than a 5.

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