Get attachment

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false. The description adds useful behavior beyond annotations: the 2097152-byte cap and the text-like/binary return behavior. This is consistent with the annotations and gives an agent extra expectations about the result.

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?

Two concise sentences, front-loaded with the core action and limitation, with no filler or redundant restatement of the schema. Every sentence 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 simple download operation, the description covers the key output behavior and a hard constraint. Since there is no output schema, the description appropriately explains text vs binary results. It lacks a broader workflow or error-context, but the input schema and annotations cover most of the remaining needs.

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 80%, so most parameters already carry their own meaning. The description does not add parameter-level detail, but the baseline of 3 applies because the schema does most of the work. The size/return-type notes are attachment-level behavior, not parameter semantics.

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 opens with a specific action, 'Downloads one attachment', and adds a precise size limit. It clearly scopes the tool to a single attachment, distinguishing it from sibling tools like get_message and upload_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?

Usage is implied by the name and description, but there is no explicit when-to-use or when-not-to-use guidance. It does not mention alternatives or that the caller should first obtain the part id via get_message, which the schema references but the description does not.

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