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

With no annotations provided, the description carries the full burden of behavioral disclosure, but it only describes return fields. It does not state that the operation is read-only, mention permissions, pagination, or any side effects, leaving key behavioral traits unaddressed.

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 concise sentence with no wasted words, but it is a noun phrase fragment rather than a complete thought, reducing front-loaded clarity. It is appropriately sized for a zero-parameter tool but could be better structured.

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 empty input schema and no output schema or annotations, the description does provide the key return fields (agents, last used, which one you are), which is adequate for a simple list tool. However, it omits whether the result is a list, ordering, or any scope limitations, leaving some contextual gaps.

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 the baseline is 4. The description does not need to explain parameter semantics, and there is no schema content to compensate for.

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 conveys the resource (agents with keys to the account) and the data returned (last used, which one you are), but never states an action verb like 'list' or 'returns'. It is not a tautology, yet it is vague about what the tool actually does and does not clearly distinguish itself from siblings like whoami or agents.revoke.

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?

There is no explicit guidance on when to use this tool versus alternatives such as whoami or agents.revoke. The description is purely declarative about output content and provides no context, prerequisites, or exclusions.

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