list_mailboxes

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

Annotations already declare readOnly, idempotent, and non-destructive behavior. The description adds meaningful beyond-annotation context with 'isolated failures', disclosing that failures on one account do not prevent results for others. It also emphasizes 'exact' mailbox names, which hints at precision behavior.

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?

A single concise sentence that front-loads the core operation ('List exact mailbox names') and packs in the key constraints: account count and isolated failure behavior. No filler or redundancy.

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 simple one-parameter read-only tool with a rich annotation set and an output schema, the description covers the essential constraints: what is listed, for how many accounts, and what happens on partial failure. Nothing critical is missing for correct invocation.

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?

Schema description coverage is 0%, but the single parameter account_ids is largely self-explanatory. The description adds value by specifying the '1-10 accounts' count constraint and per-account isolation, but it does not detail ID format, ordering, or error semantics beyond isolation.

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 exact mailbox names') and scopes it clearly to '1-10 accounts'. It is immediately distinguishable from sibling tools like list_accounts, which lists accounts rather than mailbox names.

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 gives clear context for when the tool is appropriate: when you need exact mailbox names for a bounded set of 1-10 accounts. It does not name explicit alternatives or exclusion cases, but the resource and scope make the intended use apparent.

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