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

Annotations already cover readOnly/idempotent/non-destructive, so the bar is lower, yet the description adds genuine behavioral context: the price is "vérifié de moins d'1 h ou null" (data-freshness semantics) and « Notre choix » is the first currently purchasable product. These details are not derivable from the annotations and help an agent interpret the response correctly.

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?

A single dense sentence that front-loads the content overview and ends with the recommended use case. Every clause carries information about what is returned; only the enumeration of return fields makes it slightly long, but nothing is wasted.

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?

With no output schema, the description correctly carries the burden of describing the return payload (short answer, criteria, top pick, ranking with URLs) and data freshness. Safety is covered by annotations. It is nearly complete for a single-parameter read tool; only sibling routing is missing.

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 100% and the slug parameter is documented with an example ("meilleures-pates-sans-gluten-2026") plus a pointer to list_comparatifs. The description adds no further parameter meaning, so the baseline of 3 applies.

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 the verb-resource pairing ("Détail d'un comparatif") and enumerates the returned content: editorial short answer, selection criteria, « Notre choix », and the product ranking. This distinguishes it reasonably from list_comparatifs, though it never names that sibling explicitly, so differentiation is implied rather than stated.

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?

"Idéal pour recommander un produit en citant un classement indépendant" gives one clear use scenario, which is helpful. However there is no explicit when-not-to-use, no prerequisites, and no routing to alternatives like list_comparatifs or get_product for cases where a full comparatif is not needed.

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