add-mail-attachment

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

Annotations indicate this is a destructive (destructiveHint: true) and open-world (openWorldHint: true) operation, but the description doesn't add meaningful behavioral context beyond what annotations provide. It doesn't explain what 'destructive' means in this context (does it modify existing messages?), what authentication is needed, or any rate limits. With annotations covering basic safety profile, the description adds minimal value.

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 brief (two sentences) but the second sentence is confusing and adds little value. The first sentence states the basic purpose, but the second sentence about attachment types being 'derived from the attachment resource' is unclear and doesn't help an agent understand how to use the tool. The structure could be improved by front-loading clearer purpose information.

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 destructive tool with 4 parameters (including complex nested objects) and no output schema, the description is inadequate. It doesn't explain what happens after attachment creation, what the response looks like, error conditions, or important behavioral aspects. Given the complexity and the fact that annotations only provide basic safety hints, the description should do much more to help an agent use this tool correctly.

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 75%, so the schema already documents most parameters well. The description adds no parameter-specific information beyond what's in the schema - it doesn't explain the relationship between 'body' and 'messageId', what attachment types are actually supported, or how to structure the attachment data. The baseline of 3 is appropriate when the schema does most of the work.

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 states 'Use this API to create a new Attachment' which provides a verb ('create') and resource ('Attachment'), but it's vague about what specifically is being attached to what. The second sentence about attachment types being derived from the attachment resource is confusing and doesn't clarify the actual purpose. It doesn't distinguish this from sibling tools like 'upload-file-content' or 'create-draft-email' which might also involve attachments.

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 provides no guidance on when to use this tool versus alternatives. There's no mention of prerequisites (like needing a message to attach to), no comparison to similar tools (like 'upload-file-content' for general file uploads), and no indication of when this specific attachment creation is appropriate versus other attachment-related operations.

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