list_emails

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

With no annotations provided, the description carries the burden of behavioral disclosure, and it does well: it reveals newest-first ordering, pagination, date format (ISO YYYY-MM-DD), filter categories, and label-specific mailbox behavior. It does not mention edge cases like pagination limits or ordering ties, but the core behavior is transparent.

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 sentences with no filler. The most important facts are front-loaded (what the tool does, ordering, filters, date format), and the edge-case label syntax is efficiently appended.

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?

An output schema exists, so the return shape is covered elsewhere. Given no annotations and eight parameters at 0% schema coverage, the description covers ordering, filters, pagination, date format, and label behavior. It falls slightly short only by omitting the account parameter and giving no detail on how offset interacts with pagination.

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 coverage is 0%, so the description must compensate, and it does for most parameters: since/before get date format, from_addr and unread_only are implied by 'sender/unread filters,' limit/offset by 'pagination,' and mailbox by the folder/label explanation. The account parameter is not addressed, which is a minor gap among eight 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 opens with a specific verb and resource: 'List emails in a folder,' and immediately adds ordering, pagination, and filter scope. This clearly distinguishes it from siblings like get_email, search_emails, and get_thread without needing to open the schema.

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 gives clear context for when to use this tool: listing emails in a folder with optional filters, and it specifies the special mailbox syntax for ProtonMail labels. It does not explicitly state when to prefer search_emails or other alternatives, but the usage context is strong enough for an agent to choose correctly in most cases.

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