mail_list_attachments

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

Annotations already indicate readOnlyHint and destructiveHint false. The description adds specific behavioral details: it lists metadata only, does not download attachment content, and is 'inert', reinforcing side-effect-free behavior beyond what annotations provide.

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 description is two sentences, front-loads the primary action, and includes only essential details. No redundant wording or unnecessary jargon, making it highly efficient and directly scannable.

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?

The description covers the core function, non-download behavior, and pagination, which is adequate for a simple listing tool. It does not specify the shape of the returned metadata, but given no output schema and the tool's straightforward nature, it is reasonably complete. A minor gap is the lack of return format hints.

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?

The schema has no per-parameter descriptions, and the tool description provides minimal guidance. It mentions 'account-bound pagination' hinting at cursor usage, but does not explain the role of accountId, messageId, or cursor explicitly. Given 0% schema coverage, the description should compensate but does not sufficiently clarify parameter meaning.

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 the action (list), the resource (attachment metadata for a message), and explicitly distinguishes itself from downloading content. The phrase 'inert attachment metadata' and 'Does not download attachment content' make the purpose unambiguous even among siblings like mail_read_attachment.

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?

The description implies when to use this tool (when you need metadata without content) and notes 'account-bound pagination' for iteration. However, it does not explicitly contrast with mail_read_attachment or state a direct condition for when to choose this over alternatives, so it is clear but not fully explicit.

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