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

With no annotations, the description carries the disclosure burden. It does reveal two behavioral traits beyond the field names: pagination ('Page through') and optional label filtering. It does not state response shape, permissions, or ordering, and it relies on the verb 'page/list' to imply read-only 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?

A single sentence with no filler. The primary action, resource scope, and optional filter are front-loaded, and every word contributes meaning.

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?

The surface is simple and the key non-obvious behaviors (pagination, optional filtering) are stated. Still, with no output schema and no annotations, an agent is left without any explicit statement of what a mailbox item contains, whether read permissions are needed, or how cursor/limit pagination works in practice.

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 0%, so this dimension depends on the description. It clarifies that 'domain' is the domain owning the mailboxes and that 'label' is an organisation-label filter; 'Page through' gives semantic context to 'limit' and 'cursor' as pagination controls. It does not explicitly define cursor/limit interaction, but it compensates for the bare schema surprisingly well.

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 names a specific verb ('Page through'), resource ('a domain's mailboxes'), and optional filter ('organisation label'), making it immediately distinct from single-mailbox get_mailbox and mutation tools like create_mailbox/delete_mailbox. An agent can tell this is the enumeration tool for mailboxes without opening 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 intended use is implied clearly: call it when you need to page through or filter the mailboxes belonging to a domain. However, it never names alternatives (e.g., get_mailbox for one mailbox) or states when not to use it, so there is no explicit routing guidance.

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