mail_list_messages

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

With no annotations provided, the description carries the behavioral disclosure burden. It clearly discloses pagination behavior, the limit range (1-50), the use of next_cursor to continue, that it returns summaries only, and that it does not support full-text search. It does not mention auth, rate limits, or ordering, but these are less critical for a simple read listing.

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 compact sentences deliver the core action, parameter constraints, pagination rule, and a key limitation with no filler. The main purpose is front-loaded and every phrase 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?

For a tool with three simple parameters, no output schema, and no annotations, the description covers the main invocation details: target account, list scope, pagination, and non-search behavior. It could mention how to obtain account_id or what summary fields are returned, but the existing description is sufficient for an agent to call the tool correctly in common cases.

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 compensate. It does: '指定邮箱' maps to account_id, 'limit 1-50' defines the limit parameter, and '使用返回的 next_cursor 继续' explains the cursor parameter. It omits the default limit of 10, but overall adds significant meaning beyond the bare schema.

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 a specific verb ('列出') and resource ('指定邮箱收件箱邮件摘要'), and adds pagination context. It is clearly distinct from sibling tools like mail_get_message, mail_download_attachment, and mail_export_message, since it lists summaries rather than retrieving, downloading, or exporting messages.

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 usage context is implied: use this to page through inbox message summaries. It explicitly notes the lack of full-text search, which helps rule out search requests, but it does not explicitly point to alternatives such as mail_get_message for full message content or mail_list_accounts for resolving account IDs.

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