accounts

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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered. The description goes beyond them with two useful traits: it changes nothing, and a mailbox that cannot log in is reported with the reason rather than failing the whole call – an important partial-failure behavior for an agent to anticipate.

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?

Purpose and the 'call it first' instruction are front-loaded, and every clause carries information. It is a single dense paragraph that runs slightly long, but no sentence is 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?

An output schema exists so return values need no prose explanation, and the description nonetheless sketches the payload. For a no-argument, read-only discovery tool it covers purpose, ordering, failure semantics, and downstream usage completely.

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 the baseline is 4 and there is nothing for the description to disambiguate. It correctly implies no inputs are required.

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 ('List the mailboxes this app may use') and enumerates the returned fields (address, name, mode, sender name, special folders, signatures, add-ons, allowed recipients, settings link). It clearly distinguishes itself from siblings by naming folders, search and draft as consumers of its output.

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?

Gives an explicit ordering instruction ('Call it first') plus the reason: its addresses and names feed the account and scope inputs of folders, search and draft. That is a concrete when-to-use with named alternatives, not an implied one.

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