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

Annotations already declare readOnlyHint=true, destructiveHint=false, openWorldHint=false, so the safety profile is covered. The description adds real behavioral detail beyond that: results are ordered newest first, and inline images (signature logos) are silently skipped unless include_inline is true. It does not mention pagination or result caps, keeping it short of 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?

Three dense sentences, filters front-loaded, with the default-behavior caveat and the return contract following. No filler or restated metadata; every clause adds actionable 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 an 8-parameter read tool with an output schema and full annotation coverage, the description supplies filter semantics, default behaviors, and downstream IDs, which is enough to call it correctly. The unexplained `limit` parameter is the only notable omission.

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 0%, so the description must carry the burden, and it does most of it: it maps query to filename, explains participant as sender/To/Cc by address or name, spells out the kind enum, and gives the `since` format (ISO or unix seconds). `limit` is never explained, which is the one 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?

Starts with a specific verb+resource ('Find attachments') and immediately enumerates the supported filter dimensions (filename, kind, sender, participant, date, account). It also names the sibling consumers (read_attachment, save_attachment), so an agent can place it precisely in the workflow.

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 makes the retrieval context clear and routes downstream ('Returns mail_id and attachment_id for read_attachment or save_attachment'), which tells the agent what to do next. It does not, however, state when to prefer this over search_mail, so one exclusion is missing.

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