get_attachment

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

No annotations are provided, so the description carries the full burden. It says nothing about permissions required, whether the operation is read-only, whether it marks the message as read, size or rate limits, or whether the returned payload is a file path, URL, or binary blob.

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 short sentence with no fluff and the core action front-loaded. It is efficient but so terse that it borders on under-specification rather than true conciseness.

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 tool with no annotations and no output schema, the description should explain return behavior and the meaning of the index. It leaves an agent guessing at both, so it is not complete enough to invoke the tool confidently.

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?

With two parameters and only 50% schema description coverage, the description must compensate but adds nothing. It never explains that 'id' refers to a message identifier or what the numeric 'index' selects, so the undocumented index parameter remains ambiguous.

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 pairs a specific verb ('Download') with a specific resource ('an attachment of a message'), so an agent can tell it apart from read_message or get_mailbox_info. However, it doesn't clarify what the download yields (binary content, a URL, or metadata), which leaves the purpose slightly incomplete.

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?

There is no when-to-use guidance, no alternative named, and no exclusions. The phrase 'of a message' only weakly implies the workflow (fetch a message, then its attachment) and no sibling such as read_message is referenced.

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