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

The annotations already flag readOnly/openWorld/non-destructive, and the description adds meaningful behavior beyond them: no authentication required, no personal data involved, exact EHF calculation with 12€ débours and the 7€ Alsace-Moselle adjustment, plus hard caps. This is substantial behavioral context.

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 high-value pricing statement is front-loaded and every clause carries information. It loses a point for minor redundancy ('coût, tarif, « combien coûte »') and for packing the EHF rules into a dense paragraph rather than clearer structure.

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?

The description is nearly complete: it gives pricing logic, caps, and the localisation exception, and the output schema presumably covers the response. It does not explicitly address copropriete=true or type_combinee=ciblee in the fee calculation, though the schema documents those fields.

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?

Although schema coverage is 100%, the description enriches the parameters with the fee formula, cap values, and when each count matters. It clarifies that omitting parameters yields only the flat fee estimate and that localisation_bien is not needed for the public EHF price, adding real decision value beyond the schema.

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 opens with a specific verb and object: 'Donne le PRIX ... d'un service HEL', then clearly distinguishes public pricing from subscription-level pricing. It also explicitly scopes the main special case (EHF), making the tool's purpose unmistakable and easy to separate from the orientation siblings.

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?

It gives actionable usage context: provide type_recherche and the count parameters for an exact EHF quote, otherwise only the flat fee is estimated; localisation_bien is required for packs and situation_patrimoine. It does not explicitly name alternatives such as hel-tarifs-abonnements or state when not to use the tool, so it stops short of a 5.

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