get_billing_explainer_per_payer

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

The description states it 'Returns' data, aligning with the readOnlyHint annotation and no destructive effects. It does not mention any side effects or additional behaviors, but the annotations cover the safety profile, so the description adds modest value.

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 two concise sentences with no redundant information. It is well-structured and directly communicates the core functionality without unnecessary detail.

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?

While the purpose is clear, the description lacks contextual information about parameters, input requirements, or typical use cases. It does not mention the optional customerContext or the required invoiceMonth format, leaving the caller to infer from the schema alone.

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 description does not explain any of the three parameters (X-Tenant-Id, invoiceMonth, customerContext). It only implicitly references invoiceMonth via 'month-over-month', but provides no details on expected formats, optionality, or usage of the others.

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 function: explaining month-over-month changes in invoiced cloud costs, and specifies it returns cost changes per payer. This is specific and distinguishes it from broader invoice or cost tools.

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 provides no guidance on when to use this tool versus alternatives (e.g., get_entity_invoice_explainer, get_invoice). It does not mention prerequisites, context, or scenarios where this tool is preferred.

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