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

Annotations already cover the safety profile (readOnlyHint, non-destructive, closed-world), so the description's added value is behavioral detail: `famille`+`parametres` entries are validated (out-of-series refused, French 24 Dec 2015 accessibility decree) and exported to IFC as a shared-geometry door/window type. It also notes the tool is free and needs no key, which is genuinely useful. The status of the enumerated joinery list versus the later validation/export flow is slightly blended, 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 trigger condition is front-loaded in the first clause and the sentences are dense but purposeful. The long parenthetical enumerations of family types are borderline but serve discoverability, since there is no schema or output schema to list them elsewhere.

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 input parameters and no output schema, the description carries the burden of explaining what the call yields and it does so: the family catalog with bounded parameters and bay sizes, plus the validation and IFC export behavior. It is nearly complete, missing only how the list is delivered (grouping, paging, format).

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?

The tool takes zero input parameters, so per the rubric the baseline is 4. The description references the payload fields that matter downstream (`famille`, `parametres`, `ouvertures[]`), but since there is no input schema to disambiguate, it cannot exceed the baseline.

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 a concrete verb and resource: it lists parametric joinery families (hinged/double/sliding/pocket/entrance doors, French windows, sliding patio doors, tilt-and-turn/fixed windows) with their bounded parameters and resulting bay sizes. That is far more specific than the title. It does not, however, explicitly distinguish itself from near-siblings such as cao_bibliotheque_familles or cao_famille_essayer, so it falls short of a 5.

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?

Usage is clearly framed: 'WHEN you place doors or windows in a scene and want real, orderable joinery instead of free-size holes.' This gives an unambiguous trigger context. It never names an alternative tool or states when NOT to use it, so it stops short of the top band.

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