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

Annotations already declare readOnlyHint=true, openWorldHint=false, destructiveHint=false, so the safety profile is clear. The description adds that the tool performs a comparison between two repayment strategies, which hints at output content, but discloses no further behavioral traits such as calculation assumptions or output format.

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 a single, front-loaded sentence with no filler, making it highly concise. However, given the tool has five parameters and no output schema, it is arguably too terse to be optimally structured for the task.

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 5-parameter calculator with no output schema, the description is incomplete. It states the high-level purpose but omits parameter details, output format (e.g., savings amount, new payment/term comparison), and when to use this tool over sibling calculators, leaving significant gaps for correct invocation.

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 only 40% (tin and comision_pct only), and the description provides zero parameter semantics. The three required parameters (capital_pendiente, meses_restantes, importe_amortizar) have no explanations in either schema or description, leaving the agent to infer units and meaning from names alone.

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 states a specific calculation: savings from early repayment, comparing reduce installment vs reduce term. It clearly differentiates from sibling calculators (cuota, capacidad, cambio) by focusing on amortización anticipada, though it does not name any 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?

The description implies usage (when evaluating early repayment and comparing two strategies) but offers no explicit when-to-use guidance, prerequisites, or alternatives like mortgage_calcular_cuota. Usage context is inferred from the purpose statement.

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