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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so 'read-only, no network' partially repeats structured data. The description nevertheless adds genuinely new behavioral facts: determinism (same input → same output) and concrete limits (64 KB input, 1 s per call, 1 MB result).

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?

Well front-loaded: computation first, then when/not-for, then side effects and limits. The only inefficiency is the full Spanish/English duplication, which roughly doubles length without adding information, though it is consistent for a bilingual toolkit.

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?

An output schema exists, so return values need not be explained, and the description covers what remains: the formula, exactness expectations, determinism, absence of side effects, and operational limits. Nothing needed to call this three-parameter financial tool correctly is 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 coverage is 100%, so the baseline is 3, but the description adds value the schema cannot: the break-even formula ties fixed_costs, price and variable_cost together and implies the price > variable_cost validity condition. It does not enumerate each parameter, which the schema already does.

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 the concrete computation ('punto de equilibrio en unidades e ingresos, y margen de contribución') and even gives the formula fixed costs / (price − variable cost per unit), so the agent knows exactly what output to expect. It explicitly contrasts with the sibling margin-markup, making selection 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?

Has explicit 'Cuándo/When' (money, tax, or financial-math results requiring exact, reproducible rounding) and 'No para/Not for' (profit, gross margin % → margin-markup). Both the inclusion and exclusion conditions are named, with the alternative sibling called out by name.

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