List mailboxes

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

No annotations are provided, so the description must disclose behavioral traits. It only states that it 'lists' mailboxes, which implies a read operation but provides no details about return format, ordering, potential errors, or whether system/hidden folders are included. The description carries minimal behavioral information.

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 a single, focused sentence with no wasted words. It is front-loaded with the action and resource, and every word contributes to 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?

For a zero-parameter, no-output-schema, simple listing tool, the description is complete enough. It specifies the scope (all mailboxes on the account via Bridge) and the absence of parameters means there is no additional input context needed. The tool's function is fully captured.

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 has zero parameters and the schema is empty, so the schema provides complete coverage. The description adds no parameter-specific meaning, but the baseline for zero parameters is 4, which is appropriate.

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'), a clear resource ('mail folders/mailboxes'), and scope ('all... on the Proton Mail account via Bridge'). It clearly distinguishes from sibling tools that deal with messages (list_messages, search_messages, get_message).

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 clearly implies this tool is for enumerating mailboxes, and the context provided by sibling tool names (message-focused) makes the appropriate use case evident. It doesn't explicitly state exclusions or alternatives, but the distinction is clear from the naming.

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