list_mailboxes

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

With no annotations, the description carries the full burden of behavioral disclosure. It clearly states the operation is a listing (non-mutating) and specifies the return fields (account name, mailbox path, message count). It does not need to warn about side effects because a list operation has none.

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 two sentences long, front-hoaded with the action, and contains no fluff. Every sentence contributes: the first defines scope, the second defines the output contract.

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?

This is a simple zero-parameter listing tool. The description states the full scope and the returned fields, and an output schema exists to define the exact return shape. Nothing relevant is mising.

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 input schema has zero parameters, so the baseline is 4. The description adds no parameter information because there are no parameters to document; schema coverage is 100% by virue of noparams.

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 states a specific verb ('List') and a clear resource ('all mailboxes across all configured MailMate accounts'). This differentiates it from sibling tools like list_tags or search_messages_tool, which operaze on different entities.

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 implies the tool should be used when a user needs to enumerate mailboxes across accounts, but it does not explicitly mention when to prefer it over alternatives or when not to use it. Since siblings have distinctly different purposes, the implication is sufficient but not stated.

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