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

Annotations indicate readOnlyHint=true, so the description doesn't need to emphasize non-destructiveness. It adds context about the calculation logic (e.g., no descendants → ascendants legítima, CC art. 809) and notes what it does NOT calculate (succession tax). However, it doesn't mention potential complexity like regional variations in detail or that results are estimates; still, the description aligns with readOnlyHint and adds some behavioral context, so a 3 is fair.

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 concise, front-loaded with the core purposeaine and exceptions, and every sentence adds value. It mentions what it returns, conditions for ascendants, and a cross-reference to the sibling tool. No redundancy with schemas.

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?

The description is comprehensive for a tool without an output schema: it lists the outputs (legítima total, part per child, tercio de mejora, etc.), clarifies the ascendant case, and refers to the sibling for tax. The only minor gap is not specifying that the calculations are estimates or may require legal advice, but given the annotations and schema, the information is sufficient for an agent to invoke correctly.

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 each parameter is already described. The description adds meaning to 'tienen_ascendientes' by explaining its conditional usage and legal basis (CC art. 807/809), which is beyond the schema. However, it doesn't clarify the units or format of 'patrimonio_neto' (schema already says euros), nor does it elaborate on 'regimen' beyond the enum. Thus, a 3 is appropriate because schema does the heavy lifting but description adds critical conditional context.

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 forced heirship (legítima) under Spanish civil law, specifies the legal regimes covered, lists the returned components, and distinguishes from the inheritance tax tool (calcular_sucesiones). This is a specific verb+resource with clear differentiation from siblings like calcular_sucesiones and consulta_herencia.

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?

It explicitly states when to use it (for calculating legítima) and when not to (for inheritance tax, pointing to 'calcular_sucesiones'). It also provides conditional guidance on when the 'tienen_ascendientes' parameter is required (when num_hijos=0 and régimen 'comun') and when it is ignored (with hijos). This is exemplary usage guidance.

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