generate_due_invoice

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

Annotations already indicate this is not read-only, and the description adds little behavioral context beyond 'create an invoice.' It does not disclose the financial side effects, whether the operation is reversible, what happens after confirm=true, or what response to expect. For a billing-affecting action, this is a meaningful gap.

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 filler. The parenthetical 'whmcs/generate_due_invoice' is slightly redundant with the tool name but harmless, and the overall length is appropriate for such a small schema.

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 mutating billing operation with no output schema, the description is too thin: it omits usage conditions, side effects, and expected results. The schema covers parameters, but the tool context is not complete enough for an agent to use it confidently.

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 description coverage is 100%, with both parameters already documented (id and confirm requiring true). The description adds no extra meaning about parameter formats, constraints, or relationships, so the baseline of 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 states a clear action ('Создать следующий инвойс') and a specific target resource ('для сервера'), so an agent can tell this is an invoice-creation operation. It does not explicitly distinguish itself from sibling create_addfunds_invoice, and 'следующий инвойс' is somewhat vague, so it misses the top score.

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?

There is no guidance about when to use this tool instead of alternatives such as create_addfunds_invoice or get_server_invoices. No exclusions, prerequisites, or selection conditions are mentioned, so the agent must infer the intended use case.

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