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

No annotations are provided, so the description bears full responsibility. It discloses that the tool returns a 'sugerencia' with specific fields (clave_prodserv, clave_unidad, etc.) and 'candidatos' for alternative choices. It does not mention side effects, authorization, or rate limits, but for a simple query/transformation tool, the transparency is adequate.

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 well-structured: a clear opening sentence, a concise output summary, a usage directive, and a parameter list. No unnecessary words or repetition. Every sentence adds value.

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?

Given the tool has 3 parameters, no output schema, and no annotations, the description provides sufficient context. It covers purpose, usage timing, parameter details, and the nature of the return values (suggestion with specific fields and candidates). No critical information appears missing.

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 description coverage is 0%, but the description fully explains all three parameters: 'descripcion' as 'qué se vende', 'unidad_hint' as 'opcional, unidad de medida en palabras', and 'con_iva' as 'si el producto/servicio causa IVA 16% (default True)'. This adds essential meaning beyond the schema's field names alone.

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 explicitly states it converts a natural language description to SAT keys for invoicing, with a specific verb ('Convierte') and resource ('descripción a claves del SAT'). It clearly distinguishes from sibling tools (emitir_cfdi, preview_factura, whoami) which are about different operations like emitting or previewing invoices.

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 usage context: 'Llámalo antes de armar un concepto si no conoces las claves.' It tells when to call the tool (when keys are unknown) and implies it should be used before building an invoice concept. However, it does not explicitly state when not to use it or mention alternative tools, though the sibling tools are sufficiently different.

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