Search attachment metadata

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

Annotations already declare readOnly, idempotent, non-destructive, closed-world, so the safety profile is covered. The description adds genuinely new context beyond the schema: it never returns content bytes, and carrying-message summaries are bounded. An explicit note on result sizing/pagination behavior would have earned a 5.

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 filler, and the core capability plus the content-boundary caveat are front-loaded. Every clause 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?

An output schema exists, so return values need not be detailed, and annotations cover the safety profile. But for a 10-parameter tool with no schema descriptions, the definition is not complete enough for an agent to pick correct filter values, and it fails to point at mail_attachment_export for retrieving actual content.

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?

Ten parameters with 0% schema description coverage, and the description explains none of them — ext, dedupe, from_date/to_date, the three domain filters, limit, and carrying_messages_limit are all left opaque. Only 'bounded carrying-message summaries' loosely gestures at carrying_messages_limit. The description does not compensate for the schema gap.

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 resource (attachment-metadata result object) and enumerates its contents (attachment rows, totals, carrying-message summaries), and explicitly distinguishes itself from content-returning siblings mail_search/mail_show. It never states the filtering/search capability that the 10 parameters imply, so the verb is weaker than it could be.

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?

Gives an explicit when-not and names two alternatives: 'never returns attachment content bytes; use mail_search or mail_show for message content.' However, it omits the most relevant sibling, mail_attachment_export, which is presumably where an agent should go to actually retrieve attachment content — a notable routing gap.

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