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

Annotations already declare a safe, read-only, idempotent, closed-world lookup, so the safety profile is covered. The description adds real behavioral context beyond that: it discloses that no individual professional is named, and that the payload is regulator/register plus title meaning — a scoping disclosure the annotations cannot express.

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 dense but front-loaded sentence: country marker first, then trades, then output content, then the negative scope clause. No filler, though the parenthetical register list is heavy and slightly slows scanning.

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 only two parameters, full schema coverage, and annotations carrying the safety profile, the description supplies enough to call it correctly, and the 'names no professional' clause pre-empts a likely misunderstanding about return content. An output schema is absent, but the description sketches what is returned, which is adequate here.

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 'trade' and 'language' parameters (including the fr/nl acceptance and enum) are already documented in the schema. The description reinforces the trade list but adds no syntax, format, or constraint detail beyond it, making the baseline 3 appropriate.

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?

Names a specific scope (BELGIUM), enumerates the exact trades covered, and states the concrete output — the regulatory body or register, what the title means, and where a check is made. The country prefix and the 'names no professional' clause clearly separate it from the check_professional_XX siblings and from directory tools like trouver_professionnel_fr.

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 implied by the listed trades and registers, but there is no explicit 'use this when…' or exclusion directing the agent away from verifier_titre or trouver_professionnel_fr. The agent must infer that this is a routing/regulator-lookup tool rather than a verification or directory tool.

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