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

Annotation already declares readOnlyHint=true, so safety is covered; the description adds real behavioral context beyond that by disclosing what each returned document carries (totals, paid/pending amounts, due dates, status) and mapping to the underlying GET /payments endpoint. It stops short of describing pagination/cursor behavior or default sort order, but the added return-shape information is genuine value.

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 tight single sentence plus an endpoint tag — the document types and filter dimensions are front-loaded and nothing is padded. Slightly dense, but every clause (types, returned fields, filters) carries information an agent can use.

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?

With 14 optional parameters, 100% schema coverage, and no output schema, the description supplies a useful summary of the returned document fields and filterable dimensions. The main gap is pagination/ordering guidance (cursor_next/cursor_prev and default sort semantics), which the agent must infer from the schema alone.

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 all 14 parameters are already documented in the schema, establishing the baseline of 3. The description lists the same filter dimensions (member, company, location, document type, status, number, issue/due date) without adding syntax, formats, or semantics beyond what the schema states.

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 (List) and resource (billing documents), and enumerates the document types covered — invoices, credit notes, overpayments. It also names the key return fields (totals, paid/pending amounts, due dates, status), so an agent can distinguish it from the many other list_* siblings immediately.

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 implies usage through the filter enumeration and gives a concrete scenario ('e.g. overdue invoices'), which helps an agent know when this tool applies. However, it never states when NOT to use it or points to any alternative sibling (e.g. get_member, list_contracts, list_memberships) that might also surface billing context, leaving routing entirely to inference.

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