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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds useful behavioral detail about what the comparison produces ('winners' per criterion), which goes beyond the structured annotations without contradicting them.

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 with no filler. The core action and constraints are front-loaded, and the long criterion list is compactly parenthesized rather than bloating the sentence.

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 single-parameter, read-only comparison tool with robust annotations, the description is complete. It specifies the model count, the criteria, the winner-selection behavior, and the user intent that should trigger it. No additional return-format detail is needed given the simple input and read-only nature.

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%: the only parameter 'ids' is described as 'Liste des id de modèles à comparer' with min and max constraints. The description reinforces the 2-to-6 limit and enumerates comparison fields, but it does not need to add meaning beyond the schema since the schema already fully documents the parameter.

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 uses a specific verb ('Compare'), names the resource ('2 à 6 modèles côte à côte'), and enumerates the exact criteria compared (price, surface, insulation, etc.). It also clarifies the output behavior ('désigne pour chaque critère le modèle le mieux placé'), which clearly distinguishes it from siblings like get_chalet or search_chalets.

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 explicitly states when to use the tool: 'À utiliser quand l'utilisateur hésite entre plusieurs modèles ou demande « lequel choisir ».' This gives clear invocation context. It does not name exclusions or alternatives, 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.