whoami

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

No annotations are provided, so the description carries the full burden. It implicitly conveys that a signed-in session is required and that the call only reads data, but says nothing about behavior on an unauthenticated/expired session or whether the result can differ from a user-supplied identifier.

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 short sentence, front-loaded with the action and resource, and the parenthetical return fields earn their place by substituting for a missing output schema.

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 zero-argument identity tool with no output schema and no annotations, naming the three returned fields (id, username, name) supplies exactly the missing return-value context. Nothing further is needed to invoke it correctly.

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 takes zero parameters, so there is nothing for the schema to describe; baseline is 4. Nothing in the description contradicts or confuses the empty argument object.

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?

Specific verb ('Return') plus a precisely scoped resource ('the signed-in Beli user'), with the returned fields enumerated. It is unambiguously distinct from every listed sibling (bookmarks, guides, restaurants, referral), though it doesn't explicitly contrast itself with them.

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?

Usage is only implied: an agent can infer this is the identity/context call, but the description never says when to call it (e.g. first, to resolve 'me' for other calls) or that there are no alternatives for the same information. For a trivial zero-arg tool that omission is tolerable but still a gap.

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