whoami

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

Annotations already declare readOnlyHint=true, and the description reinforces this by stating 'read-only'. It adds valuable context beyond annotations: 'No approval needed' informs the agent that this operation is safe and unauthenticated in terms of approvals, reducing hesitation. The mention of 'WhoAmI RPC' also provides protocol context.

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, compact sentence that conveys all essential information immediately. It is front-loaded with the core action and resource, with safety context appended. Every word earns its place with no 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?

Given the tool's simplicity, an empty schema, and an output schema being present, the description is complete. It states the tool's purpose, safety profile, and protocol context. It doesn't need to explain return values because the output schema covers that.

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 has zero parameters and the input schema is an empty object, so there is nothing to explain. According to the instructions, a baseline of 4 is appropriate for no-parameter tools. The description adds no parameter information because none is needed.

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 clearly states the tool returns information about the current authenticated OliveTin user, using a specific verb and resource. It uniquely identifies this as a WhoAmI RPC, distinguishing it from all sibling tools which have different purposes.

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 context for when to use this tool is clear: whenever information about the current authenticated user is needed. It doesn't explicitly mention alternatives or exclusions, but the tool is self-contained and no alternative is relevant, so no additional guidance is required.

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