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

Annotations already indicate read-only behavior. The description goes beyond by detailing what outputs are produced (break-even year, savings, etc.) and mentions default values for optional parameters. It adds helpful context for a calculation tool.

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 paragraph that efficiently covers purpose, required inputs, optional inputs, and outputs. It is front-loaded with the main purpose. Could be slightly more structured, but every sentence adds value.

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 9 parameters and no output schema, the description lists outputs but does not specify return format (e.g., numbers vs text) or underlying assumptions (like static prices). It is fairly complete but lacks some detail for parameter-rich tool.

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?

All 9 parameters have descriptions in the schema, providing 100% coverage. The description repeats some but adds grouping (required vs optional). It does not add significant semantic detail beyond what the schema already provides.

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 specific verb 'Calcula' and the resource 'año en que un coche eléctrico empieza a ser más barato que uno de gasolina'. It distinguishes the tool from siblings like calcular_combustible and recomendar_vehiculo by focusing on the economic break-even point.

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 lists required and optional inputs, which guides usage, but it does not explicitly state when to use this tool over alternatives or when not to use it. It implies context but lacks direct exclusion or comparison with sibling calculators.

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