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

Annotations already declare read-only, idempotent, non-destructive and closed-world, so the bar is lower. The description still adds real value: it fixes the exact statutory rates applied, pins SBU 2026 at USD 482, and notes that the response also carries official sources plus a web-calculator link — a return-content hint that matters since no output schema exists.

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?

Three sentences, front-loaded with the outcome ('costo mensual y del período'), then per-country detail, then return contents. The rate lists are dense but each figure earns its place by telling the agent what is being computed.

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-parameter, no-output-schema calculator with solid annotations, this covers purpose, both country regimes and the shape of the response. The remaining gap is disambiguation from sibling calculators and how the period/months field interacts with the aguinaldo and décimo accrual.

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 the parameters are already documented. The description restates what the country choice implies (which contributions and bonuses are included per regime), which is a useful restatement but adds little beyond the enum descriptions and the 'reserva' parameter note in the schema.

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?

States a concrete resource and scope: monthly and period payroll cost for the employer, naming the specific statutory components (IPS, aguinaldo, IESS, décimos, fondo de reserva). It is distinguishable from siblings like calcular_liquidacion_laboral or calcular_impuesto_renta by the domain it covers, though it never explicitly says so.

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 says what is computed but never when to call it versus the other eight labour/fiscal calculators, nor any preconditions (e.g. that it is a projection over a period, not a settlement). An agent must infer the routing from the tool name alone.

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