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

Annotations declare readOnlyHint=true, and the description aligns by describing pure calculations. It adds value by detailing the computed outputs for each mode (L/100km, cost per km, autonomy, liters needed, total cost), which is beyond what annotations convey. No contradictions.

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 two sentences long, front-loads the mode summary, and wastes no words. Every sentence contributes value, making it highly efficient.

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 6 parameters, 2 required, and no output schema, the description sufficiently covers the two modes and what each computes. It could hint at the output format (e.g., returning numbers), but the calculator nature makes it reasonable. Overall complete for its complexity.

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 descriptions for all 6 parameters. The description adds context by explaining the two modes and their associated parameters (litros+kilometros for consumo, distanciaKm+consumoL100km for viaje), but does not add substantial meaning beyond the schema's own descriptions.

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 it's a fuel calculator with two distinct modes (consumption and trip), and its verb 'calcular' combined with 'combustible' distinguishes it from sibling calculators like 'calcular_imc' or 'calcular_porcentaje'.

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 explains when to use each mode: consumption for a real trip already taken, trip for estimating a future trip. It provides clear context but does not explicitly state when not to use this tool or mention alternatives.

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