whoami

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

The readOnlyHint annotation already marks this as a safe read operation, and the description adds the specific behavior of returning the authenticated user. It does not go beyond this to disclose additional behavioral details like authentication requirements or error cases, but with zero parameters and a simple read, the added value is modest.

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 a single sentence containing only the essential information: what the tool returns. It is perfectly concise, with no wasted words or redundant details.

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?

Given the tool has no parameters, a read-only annotation, and an existing output schema, the description provides sufficient context. It clearly states the output is the currently authenticated user, and the output schema can detail the exact structure. No additional information seems necessary for this simple tool.

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 no parameters, and the schema is empty with 100% coverage. According to the guidelines, a tool with 0 parameters gets a baseline of 4. The description does not need to explain parameter syntax, and it adds no parameter-related information beyond what the schema already shows.

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 'Return' with a clear resource 'the currently authenticated user.' This unambiguously identifies the tool's function and distinguishes it from sibling tools like list_users or get_user, since no other tool focuses on the current session's identity.

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 does not explicitly state when to use this tool over alternatives, nor does it mention exclusions. However, the name 'whoami' and description imply its singular purpose of identifying the current user, making the usage context reasonably clear even if not elaborated.

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