list_messages

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

The description adds behavioral details not in annotations: default INBOX and UID descending order. However, it does not disclose the return format (e.g., metadata vs full content), error handling, or whether it is read-only. With no annotations, the description carries the full burden but covers only basic behavior.

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 a single concise sentence that front-loads the core action and includes key default/sort behavior. No redundant or extraneous words.

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 simple listing tool, the description covers the essential context: the action, default folder, and sort order. The schema documents all parameters. However, with no output schema, the description does not explain what the response will contain (e.g., message IDs, subjects, pagination), leaving a minor gap.

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 100%, so the baseline is 3. The description adds minimal extra meaning beyond the schema, such as the default folder (INBOX) and sort order, but does not elaborate on parameter usage or edge cases.

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' = list) and resource ('邮件' = emails) with a scope ('指定文件夹' = specified folder), and it distinguishes this from siblings like search_messages and get_message by focusing on listing all messages in a folder.

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 clearly implies when to use the tool (to list emails in a folder) but does not explicitly mention alternatives or exclusions. It lacks guidance such as 'for searching, use search_messages' which would clarify selection.

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