Save an attachment

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

Annotations indicate readOnlyHint=false, so write is expected. The description adds valuable behavioral detail: it refuses to overwrite existing files unless overwrite=true. This is beyond annotations and informs the agent of side-effect conditions.

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 sentences, zero wasted words. Critical information front-loaded (main action) followed by specific constraints. Efficient and clear.

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?

Given the existence of an output schema (not shown) and low parameter count, the description covers the core behavior: saving one attachment with overwrite avoidance. It could mention potential permissions or directory creation, but it's adequate for the complexity.

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%, so description must compensate. It explains part_name (from mail_attachments) and overwrite (controls clobbering), but does not describe message_id, directory, or filename. The schema provides basic types, but the description leaves gaps for half the parameters.

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 the tool's action: 'Write one attachment to a directory on this machine.' It specifies the resource (attachment) and the scope (directory on machine). It distinguishes from siblings as the only tool for saving attachments, without confusion.

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 for use: saving an attachment, with note that part_name comes from mail_attachments. It doesn't explicitly state when not to use or list alternatives, but the purpose is straightforward and the sibling context shows no competing tool.

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