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

Annotations already declare readOnlyHint, idempotentHint, non-destructive, and closed-world behavior. The description adds meaningful context beyond that: it details the credential's scope semantics ('read' reads; 'write' creates, edits and produces), notes that platform operators are not charged to the wallet for production, and states the cost is $0. This economic and authorization context is valuable, though no rate limits or response format details are provided.

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, front-loaded sentence that begins with the tool's purpose and then enumerates the returned fields. Every clause appears to earn its place, but the dense run-on list is slightly less structured than an ideally formatted definition.

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?

With no output schema, the description carries the full burden of explaining what is returned, and it does so thoroughly: credential kind and scopes, organization details, attributed user, platform-operator charging behavior, wallet balance, offer, legal acceptance, and server version. Annotations cover the safety profile, so no critical context is missing for an agent to invoke and interpret this tool 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 are no parameter semantics to explain. Per the scoring rubric, zero parameters yields a baseline of 4. The description appropriately does not discuss parameters and focuses on the returned information.

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 explicitly defines the identity resource: the credential principal, its scopes, organization, attributed user, platform-operator status, wallet balance, offer, legal acceptance, and server version. It is immediately distinguishable from all sibling tools, which cover production operations, materials, scripts, and projects.

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 never states when to call this tool versus alternatives, nor does it specify any prerequisites or contexts. The only guidance-like information is the cost '$0', which is not usage guidance. Usage is implied by the name 'whoami' but not made explicit.

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