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

The readOnlyHint annotation already signals a safe read, and the description adds the useful behavioral detail that the call is 'Free', meaning it does not consume credits. It also clarifies the data scope: authenticated user, plan, and credit balance. It does not contradict the annotation.

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 minimal and front-loaded: it states the resource and data fields in one brief sentence and adds the cost detail 'Free' as a second short sentence. There is no wasted wording.

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-parameter read-only lookup, the description provides sufficient context: who the data is about, what fields are returned, and that it is free. The only minor gap is not describing the response format or error behavior, but this is acceptable given the simplicity of the tool and the presence of the readOnlyHint annotation.

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?

With zero parameters cardinality=0, the description carries no parameter burdenressing baseline 4. Schema coverage is trivially complete, and the description adds context about what the returned information represents.

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 identifies the tool as returning the authenticated user, plan, and credit balance. It is a resource-scoped info lookup, though it lacks an explicit verb such as 'retrieves' or 'returns'. The title reinforces the purpose, and the description is distinct enough from sibling tools like get_credits.

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?

No guidance is provided about when to use this tool versus alternatives such as get_credits. The description implies it is for current account context, but it does not state exclusions or direct the agent toward a sibling for more specific needs.

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