Show the authenticated user

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

Annotations already declare readOnlyHint and idempotentHint as true, so the description does not need to reiterate safety. However, the description adds value by specifying exactly which fields are returned (id, email, plan), which is not evident from the annotations alone. No contradictions.

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?

One clear sentence that efficiently communicates the tool's output. No wasted words.

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 that the tool has no parameters and no output schema, the description sufficiently explains what the tool returns. The lack of output schema means the description partially compensates by listing return fields. However, it does not mention any additional context like rate limits or authentication requirements, but the annotations handle safety.

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 input schema has zero parameters and 100% schema description coverage, so the description does not need to explain parameters. The description's mention of return fields adds meaning beyond the schema.

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 the current user's id, email, and plan. It is specific about what the tool outputs, distinguishing it as a self-inspection tool. However, it does not explicitly differentiate from siblings like check_subdomain, which serve 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 description implies usage when needing authenticated user details, but it does not provide explicit guidance on when to use this tool vs alternatives or when not to use it. Context signals and sibling tools suggest no overlap, so the usage is straightforward.

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