list_mailboxes

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

No annotations are provided, so the description carries the full disclosure burden, and it omits whether the operation is read-only, requires auth, how results are paginated, or whether it is scoped to a workspace. It does reveal the returned data (limits, ramp-up, DNS health), which is the only behavioral signal present.

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?

It is a single short sentence, but the phrasing 'List mailboxes Connected sending mailboxes...' reads as two concatenated fragments and the front-loaded purpose is slightly garbled. It is compact but not cleanly 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?

With no parameters and no output schema, the description partially compensates by naming the fields returned. However, it says nothing about ordering, pagination, or scope, which an agent would need for a listing tool.

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 tool takes zero parameters, so there is nothing for the description to disambiguate; baseline 4 applies.

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 ('List') and resource ('mailboxes') and enumerates the returned fields (today's limit, ramp-up, DNS health), which distinguishes it from siblings like list_domains or list_leads. It is clear, though it never explicitly contrasts itself with the other list_* tools.

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?

There is no guidance on when to use this tool versus alternatives such as list_domains, check_domain, or get_launch_checklist, all of which touch overlapping domain/mailbox concepts. The agent is left to infer usage from the name alone.

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