messagerie_telecharger_piece_jointe

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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered. On top of that, the description discloses two non-obvious behavioral traits the annotations do not: the returned content is base64-encoded, and there is a 10 MB size ceiling. That is genuine added value beyond structured fields.

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, front-loaded sentence with no filler. The output format (base64) and the hard limit (10 MB) are packed in without obscuring the core action.

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 read-only retrieval tool with no output schema, the description covers the essential contract: what is fetched, how it is returned, and the size constraint. It omits failure modes (missing attachment, exceeding the limit) and the id-acquisition workflow, but those are relatively minor for this tool type.

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?

Effective schema description coverage is essentially zero for piece_jointe_id (message_id has only a $defs one-liner), so the description carries the burden of explaining parameters but adds nothing. It never clarifies what a piece_jointe_id is, where to obtain it, or how it relates to message_id.

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: 'Télécharge une pièce jointe d'un message'. This clearly distinguishes it from the upload sibling messagerie_joindre_fichier and the unrelated documents_telecharger/casier_telecharger tools. However it does not explicitly name those adjacent tools to reinforce the distinction, so it stops short of 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?

No when-to-use guidance, preconditions, or alternatives are given. The agent must infer from the name alone that this is for retrieving an attachment rather than for viewing the message (messagerie_lire) or attaching a new file (messagerie_joindre_fichier).

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