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

Annotations already declare readOnlyHint=true and destructiveHint=false, and the description's "Lecture seule" is consistent with them. Beyond that, it discloses genuinely useful behavioral detail: the comparison is calculated rather than stored, the 4D criterion is surface-weighted, and each action has a defined result shape. Return format is still only loosely characterized, keeping it at 4.

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 single dense sentence front-loads the trigger condition and then enumerates actions; there is no filler. It is slightly overloaded with parentheticals (quantitatif, cout 5D, delai 4D pondere par la surface), but every clause carries information an agent needs.

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 three optional parameters, no output schema and read-only annotations, the description covers the essentials: when to call, which action to pick, what each action returns, and the criteria available. The one gap is the shape/source of the variantes argument (named scenes) and any limit on how many variants can be compared.

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%, so the baseline is 3. The description does add meaning beyond the schema's terse labels by stating that action=comparer is the default and what each action yields, and by tying critere to action=choisir. It does not explain the {nom, scene} structure of variantes, leaving that entirely to 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 names a specific verb and resource (comparer des options de conception / variantes A/B) and specifies that each variant is a named scene and that the comparison is computed (quantities, 5D cost, surface-weighted 4D schedule). This is far more specific than the title alone. It does not, however, distinguish itself from nearby siblings such as cao_comparer_versions or cao_bim_4d5d, so an agent must infer the boundary.

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?

"Appelez quand vous devez comparer des options de conception" gives an explicit trigger condition, and the two action branches are described with their respective outputs (action=comparer for evaluations/deltas/best-per-criterion, action=choisir for the winning variant). No exclusion or negative guidance (e.g. when to prefer cao_comparer_versions) is given, 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.