list_mails

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

No annotations are provided, so the description carries the behavioral burden. 'List' and 'Scope: mail:read' usefully indicate a read-only operation, but the description does not disclose return format, ordering, or how pagination interacts with the response. The schema covers basic defaults, so the gap is moderate.

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 short sentences with no filler: the first states the action and the main optional filter, and the second provides the security scope. Every sentence contributes information.

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 paginated listing tool, the required mailbox_id and optional folder/page/per_page are clearly represented by the schema plus description, and the scope note adds useful auth context. It does not describe the returned shape, but no output schema exists and 'list' implies a collection; the main missing piece is sibling differentiation, already reflected in the usage-guidelines score.

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 75%, so the schema already documents page, per_page, and folder. The description adds only 'filtered by folder', which aligns with the folder parameter, but does not add meaning for the required mailbox_id or any param values beyond the schema.

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?

States a specific verb and resource: lists mails in a mailbox, optionally filtered by folder. This distinguishes it from get_mail for single-mail retrieval and from mailboxes-related siblings, though it does not explicitly contrast with search_mails.

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?

No guidance on when to use this tool versus search_mails or other listing tools, and no exclusions or recommended contexts are given. The agent can only infer that this is for listing mailbox contents from the verb and resource.

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