whoami

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

With no annotations, the description carries the burden of behavioral disclosure. It clearly states this is a read-only introspection (no side effects implied), and details what is returned (key owner, account, scopes, universes, groups). It also notes the optional groups parameter and the meaning of '*' for universes. It does not explicitly state 'does not modify anything', but the nature of the tool and the details provided are sufficient for an agent to trust it as a safe diagnostic call.

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 well-structured in three short paragraphs: purpose, usage context, and return details. It is front-loaded with the core action, avoids filler, and every sentence provides useful information (e.g., the wildcard meaning, the group mention). No redundancy or unnecessary verbosity.

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?

For a tool with a single optional parameter and no output schema, the description is thorough: it covers the problem it solves (anonymity), when to invoke it, what it returns, and the optional behavior. It even provides troubleshooting context (missing scope, disabled key, wrong universe). This is complete for an agent to decide to call it and understand its output.

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 coverage is 100% (only one boolean parameter with a clear description). The description adds value by explaining why the includeGroups parameter is useful ('usually where a studio's real titles live') and its default behavior. This goes beyond the schema's bare description and justifies the parameter's purpose in practice.

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 states a specific verb ('Identify') and resource ('the owner of the configured API key') and explicitly differentiates from sibling tools by emphasizing that it reveals the caller identity, which is otherwise anonymous. It also lists what it returns (key name, account, scopes, universes), making its 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?

The description gives explicit when-to-use guidance: 'call this first whenever you need to know whose experiences these are, or when a query fails and you cannot tell whether the cause is a missing scope, a disabled key, or the wrong universe.' It also clarifies that Open Cloud keys are anonymous, which directly informs when this tool is necessary. No alternatives are mentioned, but the context is clear and actionable.

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