Get Mailbox Identity

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

The annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, and openWorldHint=true, so the safety profile is fully covered elsewhere. The description adds only the payload hint (sender identity plus display name) and no note on what happens if the credential is multi-mailbox, so it contributes marginally beyond structured data.

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?

Two short sentences, zero filler, with the action stated first and the usage timing second. It could consolidate into one sentence, but nothing is redundant.

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 and annotations are rich, so the description needn't explain return values or safety. For a no-required-parameter read tool this is nearly sufficient; the only real gap is disambiguation from sibling identity and sender-choice tools.

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 100% and the single parameter mailbox_id is already documented in the schema with the omission rule for single-mailbox credentials. The description never mentions mailbox_id, so it adds no meaning beyond the schema; baseline 3 applies.

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 uses a specific verb ('read') plus the resource ('mailbox sender identity and display name'), which is more precise than the title alone. It doesn't differentiate itself from close siblings like mailbox_list_identities, mailbox_get_sender_choices, or mailbox_get_me, so an agent still has to infer which 'identity' tool applies.

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?

'Use it before composing replies when the sender should match the mailbox identity' gives a concrete triggering condition rather than vague intent. It stops short of exclusions or naming alternatives, so an agent comparing it against mailbox_get_sender_choices gets no tie-breaker.

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