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

Annotations declare readOnlyHint=true, and the description confirms it's a calculation (no side effects). It adds value by explaining the formula and the exemption condition, which helps the agent understand the behavior beyond the annotation. The description does not mention any auth or rate limits, but given it's a read-only calculator, this is acceptable.

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 three sentences long, front-loaded with the core purpose, and no redundant information. Every sentence adds value: purpose, formula with exemption, alternative tool. It is highly concise and well-structured.

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 6 parameters with 100% schema coverage, no output schema, and moderate complexity, the description is fairly complete. It explains the calculation, a key exemption, and provides an alternative. However, it does not describe the output format or indicate whether the result can be negative (e.g., if deductions exceed income). This slight gap prevents a perfect score.

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 100%, so baseline is 3. The description adds moderate value by explaining the formula (e.g., '20% del rendimiento neto acumulado (ingresos − gastos) menos retenciones y pagos fraccionados anteriores'), which conceptually ties parameters together. It also covers the boolean parameter (mas_70pct_con_retencion) via the exemption condition. This provides semantic context beyond individual parameter descriptions.

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 calculates the quarterly fractionated payment of IRPF for autónomos in estimación directa (Modelo 130). It specifies the exact tax form and regime, and differentiates from sibling tools like consulta_autonomo by mentioning it for global view. The purpose is specific and 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?

The description gives explicit when-to-use context (quarterly IRPF payment for autónomos in estimación directa) and a condition for non-obligation (>70% income from clients that withhold). It also provides an alternative tool (consulta_autonomo) for a global view. However, it does not explicitly distinguish from other calculation tools like calcular_irpf or calcular_cuota_autonomo, so guidance is slightly incomplete.

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