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

The annotations already declare readOnlyHint=true and destructiveHint=false, and "Lecture seule" merely restates that, so no credit there. The description does add real behavioural context beyond the annotations: the concrete acceptance thresholds (épaisseur >= 15 mm, finition gratte/taloche/projete, support préparé) and the caveat that the verdict is indicative. It does not say what the check actually returns (findings list? pass/fail per rule?), which is the main remaining gap.

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 front-loaded paragraph that opens with the call condition and then packs the rule codes, the payload shape and the disclaimer. Dense but every clause (thresholds, enum values, caveat) carries information; the rule-code tokens add some visual noise for a marginal benefit.

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 one-parameter, read-only verification tool with no output schema, the description covers input semantics and the rules well. What it leaves out is the shape of the result — whether the agent gets a per-rule verdict, a list of non-conformities, or a free-text report — which matters for a checking tool whose whole value is the output.

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% and the schema's nested-object text is essentially identical to what the description repeats, so the baseline would be 3. The description goes slightly further by defining expected value vocabulary for finition (gratte/taloche/projete) and the 15 mm threshold that makes épaisseur_mm meaningful, which the schema does not state.

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 (VERIFIER) and a precise resource (enduits de facade), then enumerates the four checked criteria with rule codes (EF-SUPPORT, EF-EPAISSEUR, EF-FINITION, EF-JOINTS). An agent can distinguish this from neighbours such as cao_bim_ite, cao_bim_bardage or cao_bim_finitions without opening the schema.

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 VERIFIER LES ENDUITS DE FACADE" gives an explicit triggering condition, and the "Indicatif — DTU 26.1 ... priment" clause tells the agent how much weight to give the result. It stops short of naming an alternative or an exclusion case (e.g. versus ITE or finitions checks), so it is clear context rather than full routing guidance.

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