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 the returned field set (document number, vendor, gross/net, pending amount, overdue flag), which is meaningful given there is no output schema, but it says nothing about pagination ceilings, result volume, or account/permission scope.

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?

Two dense sentences with the resource and its identity front-loaded, then the status vocabulary. The field enumeration is a list dump rather than prose, but every item is informative and there is no filler.

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 12 optional parameters and no output schema, the description usefully covers return contents and the status enum, but leaves the agent without sibling differentiation against bexio_list_invoices/orders and without any note on default paging behavior. Adequate, not complete, for a tool of this breadth.

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 coverage is 100%, so the baseline is 3, but the description genuinely upgrades one parameter: it defines the ambiguous enum value TODO as 'booked, not fully paid' and gives DRAFTS/PAID/OVERDUE meaning that the schema's bare 'Bill status filter' string does not. It adds no comparable semantics for the date-range, vendor, or supplier_id filters.

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 names the resource precisely and disambiguates it from customer invoices via 'Supplier bills (Kreditoren / purchase bills)', then enumerates the fields returned. It never states an explicit verb ('list'), relying on the title/name, and it does not explicitly contrast itself with the sibling bexio_list_invoices.

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 when-to-use guidance, no exclusion, and no named alternative. An agent must infer from the resource name alone that this is the purchase-side counterpart to bexio_list_invoices rather than reading any routing instruction.

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