balena_whoami

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the agent knows this is a safe, non-destructive read. The description adds little beyond restating the basic behavior (showing the account). It doesn't disclose any additional behavioral traits such as error conditions (e.g., invalid token) or whether it requires an active session. With annotations covering the safety profile, the description's contribution is limited, hence a 3.

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, succinct sentence: 'Show the Balena account associated with the API token.' It conveys the essential purpose without any fluff. It is perfectly sized for a zero-parameter tool and is front-loaded with the action and resource.

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 the tool's simplicity (zero parameters, no output schema), the description is largely complete. It doesn't specify the output format or behavior on invalid tokens, but such details may be covered by the API contract. The description is adequate for an agent to understand its purpose and call it without further clarification.

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 has zero parameters and the schema description coverage is 100% (no properties to describe). With no parameters, the description does not need to add parameter semantics, and the baseline of 4 is appropriate for a no-parameter tool.

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's purpose: to show the Balena account associated with the API token. It specifies a clear verb ('Show'), a resource ('Balena account'), and a context ('associated with the API token'). It is distinct from all siblings, which focus on listing, getting, or mutating specific resources; no other tool is described as identifying the current account.

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 that this tool is for retrieving the current account identity, but it does not explicitly state when to use it versus alternatives like balena_get_organization or balena_list_organizations. An agent might infer it is for authentication checks, but no explicit when/when-not guidance is given.

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