download_attachment

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

Annotations already declare readOnlyHint=true and destructiveHint=false. The description adds the useful behavioral detail that the result is returned as an embedded MCP resource, but it does not disclose other traits such as size limits, authentication needs, or error behavior.

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 sentence containing exactly the essential information: the action, the resource, and the output type. No filler or redundant wording; the main behavior is front-loaded.

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 read-only download, the description plus schema is mostly sufficient: required IDs are clear and the return form is stated. However, it lacks any mention of where to obtain messageId/attachmentId (beyond the schema hint), no size/format caveats, and no routing to relevant sibling tools, leaving some context unstated.

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 descriptions cover accountId and attachmentId, and messageId is self-explanatory from its name. The description itself adds no parameter-level meaning, but with 67% schema coverage and clear parameter names, the agent can infer the required identifiers without additional explanation.

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 action ('Download'), a precise resource ('an email attachment'), and the output form ('as an embedded MCP resource'). This clearly distinguishes it from sibling tools like get_email or list_emails, which handle message content or metadata, not attachment downloads.

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 guidance is given on when to use this tool versus alternatives. Sibling tools such as get_email or get_thread are not referenced, and no conditions, exclusions, or prerequisite steps are mentioned.

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