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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description still earns credit by disclosing the return structure (per-axis breakdown, date, scoring scale) and, notably, that it also returns 'what the measurement does not say' and only exposes published measurements — real behavioral context beyond the annotations.

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, front-loaded with the primary return value and then enumerating the secondary payloads; almost no waste. The phrase 'what the measurement does not say' is slightly opaque but does useful work.

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 no output schema, the description fully compensates by enumerating what comes back (score, per-axis breakdown, date, scale, caveats), and the single parameter is documented in the schema. Combined with annotations that already cover safety, an agent has everything needed to call this 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?

One parameter with 100% schema description coverage ('a host name, e.g. renault.fr'), so the schema carries the semantics and baseline 3 applies. The description only refers to 'a domain' generically and adds no format or resolution detail beyond the schema.

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+resource ('Returns the published Agent Readiness Score of a domain') and defines what the score measures (what an AI assistant can read without JavaScript), which is genuinely clarifying. It does not, however, differentiate itself from the sibling tools it sits beside (ce_qui_manque, devis, secteur, secteurs_disponibles), which is the only thing keeping it from 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?

There is no explicit statement of when to call this tool versus a sibling, nor any exclusions. The closest thing is the ownership caveat 'Only published measurements are returned; see the server instructions for who decides,' which is a governance note rather than usage guidance.

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