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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds value by disclosing the shape of the answer — the applicable title/registry (carte T, ORIAS, nomination order, etc.), the identifier to request, and where the reader can self-verify — which tells the agent this is a static advisory answer, not a live person check.

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?

One dense but front-loaded sentence that opens with the jurisdiction ('FRANCE') and then the trades and the returned content. Every clause carries information, though the parenthetical registry list makes it slightly heavy for a single-parameter tool.

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?

There is no output schema, so the description correctly spends its budget describing what comes back (registry, identifier, verification venue). Combined with annotations covering the safety profile, an agent has enough to call it correctly; the missing piece is any guidance on sibling selection within the large credential-check family.

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% and the single 'metier' parameter already lists its accepted values, so the baseline is 3. The description largely restates the same trade list (with slightly different spacing/hyphenation than the schema), adding no format, casing, or fallback guidance beyond what the schema provides.

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 gives a specific verb ('tells which official title or registry applies') plus a concrete resource and geographic scope (FRANCE, five named trades), so an agent immediately knows this returns a reference mapping rather than a lookup of an individual. It does not, however, explicitly distinguish itself from the generic 'verifier_titre' or 'trouver_professionnel_fr' siblings, so it stops 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 only implied: the agent can infer you call it with a trade to learn the applicable registry and identifier. There is no explicit when-to-use, when-not-to-use, or routing to the many sibling credential tools (verifier_titre, check_professional_uk/au/in, verify_license_us), which is a real gap given how crowded this family is.

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