Get the mailbox profile

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

Annotations already declare readOnlyHint=true, openWorldHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is fully covered. The description adds what the query returns—profile fields—and characterizes the call as the cheapest verification of OAuth credentials, implying minimal overhead. No contradiction exists.

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 sentence that front-loads the primary behavior ('Returns the authenticated mailbox's profile') and enumerates the fields. The parenthetical examples are brief and useful, making every phrase informative without padding.

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?

With no input parameters and a read-only annotation set, there is little an agent needs to know beyond what the tool returns; the description covers the key fields and even adds a practical use case. The absence of an output schema is mitigated by the explicit field list.

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?

There are zero parameters, so the schema is fully described by its empty object and there is nothing to document. The description's mention of the response fields is not parameter semantics but does give the agent insight into what it gets back.

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 the specific verb 'Returns' and identifies the resource as 'the authenticated mailbox's profile', enumerating the exact fields (emailAddress, messagesTotal, threadsTotal, historyId). This clearly differentiates it from sibling tools that operate on messages, threads, drafts, or labels.

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 explicitly states the tool is 'The cheapest way to verify that the OAuth credentials work', which tells an agent when to use it. It also mentions the emailAddress field is useful for send-to-self checks and recognizing the user's messages, providing practical context. It does not name exclusionary alternatives, but the resource is unique among siblings.

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