whoami

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

The description discloses that the tool reveals identity, active account, and permissions. With no annotations, the description carries the burden; it implies a non-mutating read operation but does not explicitly state no side effects or prerequisite authentication, though the verb 'Show' makes this clear.

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 two sentences, front-loaded with the core action, and the second sentence adds practical usage guidance without fluff. Every sentence earns its place.

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?

The description covers what the tool does and when to use it. The output schema exists, so return values need not be explained. It doesn't explicitly compare with siblings, but the 'use this first' guidance provides context. For a zero-parameter tool, this is adequate.

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, and schema coverage is 100% vacuously. The description correctly avoids discussing parameters. Baseline for zero params is 4, and nothing more 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 uses a specific verb 'Show' and clearly identifies the resource: current API user's identity, active account, and permissions. This distinguishes it from sibling tools like list_accounts and switch_default_account, making the tool's purpose unmistakable.

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?

It explicitly says 'Use this first' to understand the account and permissions, providing a clear when-to-use directive. It doesn't explicitly mention when not to use it or name alternatives, but the contextual guidance is clear enough for a 0-parameter tool.

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