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

With no annotations, the description carries the full behavioral burden and does so thoroughly: it copies as-is, supports any file type up to 10 MB, does not read the content, defaults the destination and name, and even discloses the duplicate-file behavior ('Drive allows two files with the same name in a folder, so calling this twice makes a second copy').

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 front-loaded with the core action and every sentence adds information: size limit, destination rules, naming default, and duplicate behavior. It is slightly longer than strictly necessary, but zero sentences are wasted.

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 5-parameter, no-output-schema tool, the description covers the critical invocation facts: where IDs come from, destination behavior, naming, and file-size constraints. The only notable gap is that it does not describe what the tool returns after a successful copy, which would matter more given the missing output schema.

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 60% and the description adds genuine meaning to parameters: parentItemId is tied to folder listing tools and My Drive root, name defaults to the attachment's name, and attachmentId is sourced from get_gmail_message. messageId remains less explicitly defined, but its role is inferable from the opening sentence.

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 verb and resource: 'Copy one attachment of a Gmail message into this account's Google Drive, as-is'. It also differentiates from siblings by noting it copies without reading, which distinguishes it from read_gmail_attachment, and names Gmail/Drive specifically versus the Outlook/OneDrive sibling.

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 description gives clear context on when to use it and where supporting data comes from: 'Get attachmentId from get_gmail_message', and parentItemId 'from list_gdrive_items or search_gdrive_items'. It implies the reading alternative via 'without reading it', and explains root-folder behavior when parentItemId is omitted, but it does not explicitly state when to prefer a read tool over this copy tool.

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