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

With no annotations, the description carries the full burden. It discloses useful behaviors: automatic decoding of quoted-printable/base64 and UTF-8, and extraction of links/attachments. However, it does not mention whether reading the mail has side effects (e.g., marking as read) or how attachments are returned, which are relevant for a mail-fetching tool.

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?

Three short sentences with no filler. The access restriction is front-loaded, followed by the action and the UID source, then the decoding behavior. Every sentence adds value.

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 tool with no output schema and no annotations, the description covers the main action, input source, decoding, and access restriction. However, it omits the return format for attachments/links and any error or side-effect behavior, leaving an agent to guess at the response shape.

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 50%: uid has a description, auth_token does not. The description adds that UID comes from imap_list_inbox, which is helpful, and hints at token usage ('RÉSERVÉ AU STUDIO (token)'), but it does not clarify auth_token's format, source, or whether it is required despite being optional in 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?

The description clearly states a specific verb ('Récupère') and resource (body, links, attachments of an INBOX email by UID), and distinguishes itself from imap_list_inbox by noting the UID comes from that sibling. This is unambiguous and differentiates the tool from siblings.

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 explicitly says the UID is provided by imap_list_inbox, establishing a clear workflow, and warns that the tool is reserved for studio token holders. It does not explicitly name alternatives or when-not-to-use conditions, but the context is sufficient for an agent to sequence calls.

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