get_server_invoices

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

Annotations already declare readOnlyHint and openWorldHint, covering the safety profile. The description adds minimal behavioral context via the plural 'invoices' and the internal WHMCS endpoint reference, but it does not describe output shape, pagination, ordering, or possible empty results. This is acceptable for a simple read-only lookup but adds little beyond annotations.

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, front-loaded sentence with no redundant words. The parenthetical backend reference is useful and compact, making the definition appropriately sized for the tool's simplicity.

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 one-parameter read-only lookup, the description plus schema is sufficient for an agent to call it correctly: it knows the required server id and that the result is invoices related to that server. A minor gap is the lack of explicit output structure or differentiation from get_server_billing_data, but this is not blocking.

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 input schema has 100% description coverage for the only parameter, id, described as 'ID сервера'. The tool description itself adds no parameter-level detail, so the baseline score of 3 applies.

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 'Инвойсы, относящиеся к конкретному серверу' clearly identifies the resource (invoices) and the scope (a specific server), which aligns with the tool name. It does not use an explicit verb like 'list' or 'retrieve,' but the meaning is unambiguous and distinguishable from generic invoice tools by the server scoping.

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?

Usage is implied: call this tool when you need invoices tied to a particular server. However, it does not explicitly state when to prefer this over siblings like get_invoices, get_invoice, or get_server_billing_data, nor does it mention any exclusions or fallback conditions.

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