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

The annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds valuable behavioral context: it returns arithmetic breakdown, not just the total; it explains why the subtotal is not a final price; and it notes that the response itself explains the tax exclusion. This goes beyond the annotations by disclosing the nature of the output and a caveat about its interpretation.

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 moderately sized but packed with essential information. It front-loads the core purpose, then explains the cycle parameter, then provides the critical tax caveat. Every sentence earns its place, though the tax warning could be slightly more concise. The structure is logical: purpose → parameter semantics → important caveat.

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 the tool has an output schema (which likely explains the response structure), the description doesn't need to detail return values. It covers the key contextual aspects: how to determine available cycles, the default behavior, and the tax caveat. It could potentially mention what happens with invalid cycle values, but the description is largely complete for an agent to invoke it 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 0%, so the description must compensate. It does: it explains the 'cycle' parameter in detail (accepts code or name, examples, default behavior), and it clarifies that 'quantity' and 'name' are used for the quote. It doesn't explicitly define 'name' or 'quantity' beyond the schema, but the overall purpose makes them inferable. The cycle parameter gets rich semantic treatment, which is the most complex parameter.

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's purpose: 'Cotiza un plan por cantidad y período' (quotes a plan by quantity and period) and explicitly says it returns the arithmetic, not just the total. It distinguishes itself from siblings by mentioning get_product for cycle details, and the verb 'cotiza' is specific to the quoting action.

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 provides explicit usage guidance: it explains how to specify the cycle (code or name, with examples), what happens if cycle is omitted (defaults to main period), and where to find the available cycles (prices in get_product, available_cycles). It also gives a critical usage warning about the subtotal not including taxes, which must be communicated when presenting results. This is clear when-to-use and how-to-use guidance.

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