list_billing_invoices

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

No annotations are provided, so the description carries full burden. It discloses the tool lists all invoices and returns specific fields, but does not mention pagination, ordering, rate limits, or any destructive behavior. Given no contradiction with annotations (none exist), it is adequate but not comprehensive.

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 sentences long, front-loaded with the primary purpose, and includes an additional note for an alternative output. Every sentence adds value; no waste.

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 a simple list tool with one parameter and no output schema, the description adequately covers what is returned (IDs, dates, amounts) and points to a focus spec resource. It lacks pagination details but is sufficient for the complexity level.

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?

Schema coverage is 100% (the 'contract' parameter is described in the schema). The description adds no additional meaning beyond what the schema provides, so baseline 3 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 action ('List all invoices'), the resource ('for your IONOS CLOUD contract'), and the output ('Returns invoice IDs, dates, and amounts'). It distinguishes from siblings like get_billing_invoice (single) and list_billing_invoices_by_period (filtered).

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 mentions an alternative for FOCUS v1.3 output but does not explicitly state when to use this tool vs siblings like list_billing_invoices_by_period or get_billing_invoice. Usage context is implied but not specific.

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