list_attachments

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

With no annotations, the description carries the full behavioral burden. It does disclose the key trait that content is not downloaded, which is important for an agent deciding between listing and downloading. However, it does not mention return shape, side effects, permissions, or whether metadata like filenames and sizes are included.

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 a single, front-loaded sentence with no filler. The parenthetical adds a necessary distinction and every word earns its place.

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 two-parameter, list-only tool with no nested objects, the description plus full schema coverage is nearly sufficient. The only gap is that no output schema exists and the description does not specify what attachment metadata is returned, but this is a minor omission for such a simple listing operation.

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 100%, so uid and mailbox are already fully documented. The description itself adds no additional parameter-level meaning, but the schema already carries the load, so the baseline score of 3 is appropriate.

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 ('all attachments in an email'), and the scope boundary ('without downloading content'). This distinguishes it from download_attachment and save_attachment without needing to inspect their schemas.

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 parenthetical gives a clear context: use this tool when you need to see what attachments exist without retrieving their contents. It implies the alternative of downloading/saving attachments for actual content, though it does not explicitly name those sibling tools or give exclusion criteria.

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