get_invoice

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds no behavioral detail beyond its purpose—no mention of response content, authentication needs, pagination, or edge cases. It neither contradicts nor meaningfully extends the annotation data.

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?

A single front-loaded sentence states the resource and operation without wasted words. The parenthetical endpoint name is compact and useful for traceability. The description is appropriately sized for such a simple tool.

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 read-only single-parameter tool with high schema coverage and no output schema, the description provides enough to understand the core purpose. It could be more complete by naming alternatives or indicating the shape of the returned invoice data, but these are minor gaps given the tool's simplicity.

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%: the only parameter invoice_id is documented as 'Номер инвойса'. The tool description does not add further parameter context, but with full schema coverage 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 clearly identifies the resource as 'конкретного инвойса' (a specific invoice) and the operation as retrieving its data, which distinguishes it from the sibling get_invoices. However, it lacks a strong imperative verb and the parenthetical 'whmcs/get_invoice' is useful but slightly cryptic.

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 given about when to use this tool versus get_invoices or download_invoice. The phrase 'для оплаты' hints at a payment context, but it does not explicitly state when this tool is preferred or how it differs from related invoice tools.

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