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

Annotations already declare readOnlyHint, non-destructive and closed-world, so safety is covered. The description adds valuable behaviour beyond that: only the *published* fiche is returned, and it enumerates the payload sections. It doesn't say what happens for an unknown or unpublished slug (error vs empty), which is the remaining gap.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?

Two sentences, zero filler: the first front-loads what is returned and its sections, the second gives the only non-obvious calling constraint. Every clause earns its place.

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, but the description enumerates the returned content (coverage, exclusions, sinistre examples, risks, FAQ, URL), which substitutes for it. Combined with the single documented parameter and the annotations, an agent has everything needed to call it correctly.

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 0% (slug is type-only), so the description must carry the burden — and it does: it explains the slug's origin ('vient de rechercher, type « metiers »') and gives example values (plombier, électricien, maçon). Format details (accent/case handling, exact slug syntax) are still unstated.

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?

Specific verb+resource ('Renvoie la fiche publiée d'un métier du BTP') with a concrete inventory of what the fiche contains (couverture/exclusions décennale, sinistres, risques, FAQ, URL). This clearly separates it from lire_article (articles) and rechercher (slug discovery).

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?

It states the prerequisite explicitly: the slug must come from 'rechercher (type « metiers »)', which routes the agent to the correct upstream sibling. It stops short of naming exclusions or alternatives (e.g. when to prefer lire_article), so it's clear context but not full when/when-not guidance.

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