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

Annotations already declare readOnlyHint/destructiveHint/openWorldHint, so "Lecture seule" is redundant, but the description adds real behavioral context beyond them: the 120 mm threshold, the chevilles/rails fixing criterion, and the caveat that signed DTA and thermal calculations override the verdict. It does not state what the response looks like.

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?

Front-loaded with the trigger clause, then the check list, then the parameter shape, then the caveat — an efficient ordering with essentially no filler. Dense abbreviation (ITE-EPAISSEUR, DTA) costs some readability but not length.

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?

Given one nested parameter, no output schema and read-only annotations, the description covers input shape, thresholds and the advisory limitation well. It never indicates what the check returns or how findings are reported, which for a verification tool with no output schema is a material gap.

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% so the baseline is 3, but the description adds meaning the schema lacks: the enum for finition (enduit|bardage) and the fact that epaisseur_mm is compared against a 120 mm minimum. That makes the single nested object actionable rather than just described.

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?

States a specific verb (VERIFIER) and resource (isolation thermique par l'extérieur / enveloppe ITE) and enumerates the four concrete checks it performs (ITE-EPAISSEUR, ITE-FIXATION, ITE-FINITION, ITE-PONTS). It is distinguishable from adjacent siblings like cao_bim_ponts_thermiques or cao_bim_bardage only implicitly, since those are never named.

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 L'ISOLATION THERMIQUE PAR L'EXTERIEUR" gives an explicit trigger condition, and the closing caveat ("Indicatif — avis technique (DTA) et calcul thermique signes priment") tells the agent the result is advisory, not authoritative. No exclusion or named alternative is given.

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