mail_list_unread

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

With no annotations provided, the description carries the full burden of disclosing behavioral traits. It explains that only envelope fields are returned by default and that sort, cursor, and snippet options are available. However, it does not mention that the operation is read-only or any potential side effects, though the name implies read.

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 consists of two concise sentences that immediately convey the primary function and key options. No extraneous information is included.

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?

Given the presence of six parameters, a required mailbox, and no output schema, the description should provide more context about the response structure and pagination behavior. It mentions cursor support but does not explain the envelope fields or the difference between returnPage options, leaving some gaps for an AI agent.

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?

The input schema has 100% description coverage, so the parameter details are already well-documented. The description adds no further meaning beyond restating the availability of sort/cursor/snippet options, earning a baseline score of 3.

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 clearly states the action 'List unread messages' and specifies the resource 'in a folder', making the purpose specific. It also hints at differentiation from sibling 'mail_list_messages' by focusing only on unread 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 description does not provide explicit guidance on when to use this tool versus alternatives like mail_search or mail_list_messages. It only mentions the envelope-only default and available options, but lacks contextual cues for choosing among siblings.

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