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

Annotations already declare readOnlyHint/idempotent/non-destructive, so the safety profile is covered. The description adds real behavior beyond that: unknown or untracked domains return an error result and nothing is charged, plus a detailed account of the return payload. It doesn't mention rate limits or latency, keeping it from a 5.

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?

Purpose and usage routing are front-loaded in the first two sentences, and the long return-value enumeration is justified because no output schema exists. It is dense but earns most of its length; the payload list is slightly over-packed into one paragraph.

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 the return fields (note, etapes, faits, machine, ucp_commande, dernier_test, test_ancien, resume, page) including score breakdown and step names. Covers the error case as well, so an agent has everything needed to call and interpret it.

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%, and the schema itself documents both domaine (format/normalisation) and langue (fr/en, effect on summary). The description only implicitly touches domaine ('by domain') and langue ('one-sentence summary to quote'), adding little beyond the schema. Baseline 3 applies when the schema carries the parameter detail.

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 states a specific verb+resource+scope immediately: a full test result for ONE French online store, by domain, describing what an AI shopping agent could do there at the last test. It also explicitly names the sibling tools (trouver_marchands, rechercher_marchand, comparer_marchands) so an agent can distinguish it without opening schemas.

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?

Gives explicit when-to-use cues ('before visiting, recommending or buying from a French store', 'when the user asks if a store works with AI agents') and routes to alternatives for other jobs ('to find stores you do not know yet', 'to look up a store by name', 'to put several side by side'). Nothing is left to inference.

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