list-attachments

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

No annotations are provided, so the description carries the behavioral transparency burden. It discloses the returned fields (name, MIME type, size, count) and explicitly notes it does not return bytes, which sets accurate expectations for follow-up actions. It does not cover errors or permissions, but for a read-only enumeration tool this is acceptable.

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 four short sentences, each with a distinct role: when to use, what it returns, when not to use, and prerequisite. It is front-loaded with the core purpose and contains no filler.

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 a single parameter, an output schema, and clear usage guidance, the description covers purpose, return values, alternatives, and prerequisite in a compact form. There are no significant gaps for an agent to select and invoke the tool correctly.

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 0% and the schema only provides a regex pattern, but the description clarifies that the sole 'id' parameter is the message id and tells the agent how to obtain it. The description compensates for the lack of schema-level semantic detail by tying the parameter to its real-world use.

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 it enumerates a message's attachments by id to discover their names, MIME types, and sizes. It distinguishes itself from sibling tools by explicitly noting that fetch-attachment and save-attachment handle byte content, while this tool does not.

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 provides explicit 'Use when' and 'Do not use when' guidance, naming fetch-attachment and save-attachment as alternatives for byte retrieval. It also instructs the agent to obtain the message id from search-messages or list-messages first, giving a clear prerequisite for correct usage.

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