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 burden. It adds a useful behavioral detail by declaring 'Scope: mailbox:read', indicating the required permission. However, it does not disclose potential pagination, sorting, or return format, though the zero-parameter design makes the tool simple.

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 exceptionally concise: two short sentences, with the primary action front-loaded. Every word adds value, including the scope annotation. There is no redundancy or filler.

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 list operation, the description is nearly complete. It states what the tool returns (all mailboxes) and the required scope. It could mention whether the result is limited or ordered, but this absence is not significant given the tool's simplicity.

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 properties, so there are no parameter semantics to explain. The description appropriately focuses on the operation and scope. With 0 params, the baseline is 4, and the description does not need to compensate for missing parameter documentation.

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 and resource: 'List all Smailr mailboxes.' This clearly identifies the operation and distinguishes it from sibling tools like get_mailbox (single mailbox) and create_mailbox (new mailbox). The added scope line reinforces the read-only nature.

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 usage: use this when you need to enumerate all mailboxes. However, it does not explicitly state when not to use it or mention alternatives such as get_mailbox for a specific mailbox. The context is understandable but left to inference.

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