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

Annotations already declare readOnlyHint=true, and the description merely restates this as '(read-only)' rather than adding new behavioral context. Nothing is disclosed about pagination behavior, result caps, or authentication needs, so the description adds little beyond the structured fields.

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 with no wasted words. The trailing 'optionally for one invoice, a date range or payment types' is slightly compressed, but overall it is tight and well-structured.

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, zero-required-parameter list tool with full schema coverage, the description conveys purpose and available narrowing options adequately. It does not mention pagination or output shape, but with no output schema that omission is minor rather than disqualifying.

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%, so every parameter (from/to, page, type, user_id, order_by, per_page, invoice_id) is already documented with format and defaults. The description only gestures at the same filters, adding no syntax or format detail beyond the schema, matching the baseline for high-coverage schemas.

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?

States a specific verb and resource ('List the payments that were recorded on invoices') and scopes it with the available filters. It is distinguishable from siblings like billomat_list_invoices or billomat_list_invoice_items, though it does not explicitly name a sibling to contrast against.

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?

'Optionally for one invoice, a date range or payment types' signals the filtering contexts in which to use it, but there is no explicit when-to-use/when-not or alternative named. Usage is implied rather than stated.

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