check_inbox

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It effectively describes the return format (email summaries with specific fields) and clarifies what is not included (email body), which is valuable context. However, it lacks details on potential behavioral traits like pagination, rate limits, authentication requirements, or error handling, leaving some gaps for a tool with no annotation coverage.

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 front-loaded with the core purpose in the first sentence, followed by essential details on return values and tool differentiation. Every sentence adds value—clarifying included fields, excluded content, and when to use alternatives—with no redundant or unnecessary information, making it highly efficient and well-structured.

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 tool's moderate complexity (listing emails with filtering), no annotations, and no output schema, the description does a good job by specifying the return format and tool differentiation. However, it could be more complete by mentioning potential limitations (e.g., pagination, default sorting) or error scenarios, which would help an agent use it more effectively in varied contexts.

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 description coverage is 100%, so the schema already documents both parameters ('status' and 'mailbox_id') with descriptions and enum values. The description does not add any parameter-specific information beyond what the schema provides, such as default behaviors or usage examples. This meets the baseline of 3 for high schema coverage without additional param details.

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 specific action ('List emails in your inbox') and resource ('emails'), distinguishing it from siblings like 'read_email' (which gets full content) and 'list_mailboxes' (which lists mailboxes rather than emails). It provides precise scope by mentioning what's included (summaries with specific fields) and what's excluded (email body).

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 explicitly states when to use this tool ('List emails in your inbox') versus alternatives ('call read_email with the email ID to get the full message content'), providing clear guidance on tool selection. It differentiates from 'read_email' by specifying that this tool returns summaries only, not full content.

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