get_usage

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

With no annotations, the description must fully disclose behavioral traits. It does state the temporal scope (this month) and grouping, but it omits whether the operation is read-only, any authentication requirements, error conditions, or the structure of the response. This is minimal behavioral disclosure for a tool with no structured metadata.

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 short sentence, front-loaded with the key information: what it returns (operations and cost), the scope (this month), and the grouping. There is no fluff or redundancy, making it highly efficient.

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 low complexity (no parameters, no output schema), the description is adequately complete. It tells the agent what the tool returns and the grouping. It could be improved by a note on read-only behavior, but for a simple retrieval tool it is sufficient.

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, so the schema is empty and there is nothing to describe. Per the rubric, 0 parameters gets a baseline of 4. The description adds no parameter details (since none exist), and that is appropriate.

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: it returns operations and cost for the current month, grouped by operation. This specific verb, resource, and scope distinguish it from siblings like get_balance (which likely returns a balance) and get_pricing (pricing info), making it unambiguous for an agent to select.

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 on when to use this tool versus alternatives. The description does not mention that this is for month-to-date usage, nor does it name any sibling tools as alternatives. An agent would have to infer usage context, which is not ideal.

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