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

Annotations already declare readOnlyHint=false and idempotentHint=false, so the write/non-idempotent nature is known. The description adds genuine context beyond that: no key/authentication is needed and 'Pas de données personnelles' warns against personal data. It stops short of describing what happens after submission or any limits.

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?

The purpose and target are front-loaded, followed by inline parameter glosses and a privacy note. The content-hint list is a bit dense but each clause maps to intended message content, so little is wasted.

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?

For a simple two-parameter write tool with annotations covering safety and an output schema covering returns, the description supplies the missing pieces: parameter meanings, the optional flag, the no-auth note, and the no-personal-data caveat. Adequate and coherent.

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 0%, so the description must carry the burden, and it does: 'message' is defined as the user's text and 'looking_for' as the sought information/service, correctly flagged as optional ('facultatif'). This meaningfully compensates for the undocumented schema, though it adds no format or length constraints.

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 names a specific action (leaving a free-form message) and an explicit target (the owner of 304NotModified), so the purpose is unambiguous. It does not, however, differentiate itself from close siblings like 'feedback' or 'ask', which an agent would need in order to choose between them.

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: 'sans clé ni question préalable' hints that no prior context is required, and the content hints (what you searched for, what was missing, why you're leaving, a suggestion) frame the intended input. No explicit when-to-use-vs-alternatives guidance or exclusion against 'ask'/'feedback' is given.

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