list_unread_emails

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

No annotations are provided, so the description carries the full burden. It discloses the result order (newest first), the returned fields, and the attachment indicator, which adds meaningful behavioral context. However, it does not mention potential side effects (e.g., whether reading changes read state) or error/empty behavior, leaving some room for improvement.

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 two concise sentences, front-loaded with the core purpose. Every clause adds value: the output fields and attachment indicator are essential information. No wasted 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 list tool with one optional parameter and no output schema, the description is complete: it specifies purpose, ordering, output structure, and attachment behavior. Combining the description with the schema gives an agent everything needed to invoke the tool correctly.

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 schema already fully describes the count parameter (100% coverage) with default value, so the description adds no additional parameter-level semantics. Per the rubric, baseline 3 is appropriate when schema covers all parameters.

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 tool's function with a specific verb and resource: 'List unread emails'. It also provides key output details (ID, From, Subject, Received) and ordering (newest first), which distinguishes it from sibling tools like list_emails (all emails) and search_emails.

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 implies the tool is for retrieving unread emails but does not explicitly say when to use it versus alternatives, nor does it mention exclusions or alternative tools. There is no guidance such as 'Use search_emails for filtering' or 'Use list_emails for all emails'.

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