list_attachments

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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false and openWorldHint=true, so the safety profile is fully covered. The description adds only that results are 'metadata' (not content) and that the message must be 'owned' — modest but non-redundant context; nothing is said about pagination, empty results, or ordering.

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 efficient sentence with the resource front-loaded and zero filler. It is appropriately sized for a one-line tool, though its brevity contributes to the gaps noted elsewhere.

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, no annotations gap on safety, and three parameters at 0% schema coverage, the description should describe what attachment metadata is returned (name, size, mime type, id) and how folder/accountId affect the lookup. It supplies none of this, leaving the agent unable to predict the response.

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% and the description names none of the three parameters. The inbox/sent 'folder' enum and the 'accountId' scoping parameter are completely undocumented anywhere, and 'emailId' is only hinted at via 'owned message'. The description fails to compensate for the coverage gap.

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 and resource ('List attachment metadata') and scopes it to an owned message, which implicitly contrasts with download_attachment's content retrieval. However, it never names the sibling or clarifies the metadata-vs-content boundary explicitly, so an agent must infer the differentiation.

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, no prerequisites (e.g. that an emailId from list_messages/get_message is required), and no mention of download_attachment as the alternative for retrieving actual file contents. The agent is left to infer the call context entirely.

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