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

Annotations already declare a safe, idempotent, closed-world read, so the description's added value is in what it returns: the range in SBU/salarios mínimos and in money, the applicable article, official sources, and a web calculator link. That is meaningful extra context not derivable from the annotations, though it says nothing about precision assumptions or rounding.

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?

Four compact sentences with the legal basis and unit framing front-loaded, then the return contents. Dense but every clause carries information; only the 'Devuelve… Devuelve también…' split is slightly redundant.

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 correctly carries the burden of describing return values (range in units and money, article, official sources, calculator link). It does not state what happens for combinations like a grade supplied with a Paraguay entity, but the schema enums already scope those cases.

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 coverage is 100% with detailed per-parameter descriptions, so the baseline is 3. The description adds some legal framing (Ecuador tiers 1-10 / 11-20 / 21-40 SBU by grade; Paraguay caps of 5.000 or 500 salarios mínimos or a % of the operation) that explains how entity/grade/operation interact, but nothing beyond the schema's own text.

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 specific resource (fines for money-laundering prevention infractions) and scope (Paraguay SEPRELAD Ley 1015/97 and Ecuador UAFE), including the unit basis (SBU / salarios mínimos). It is clearly distinguishable from siblings like calcular_multas_declaracion_tardia by topic, though it never names the sibling explicitly.

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?

Usage is only implied: the agent must infer that this tool is for LA/FT fine ranges rather than other fine or tax calculations. There is no explicit 'use when' statement, no exclusion of the sibling multas tool, and no note on preconditions (e.g., needing to know the entity type first).

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