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

readOnlyHint=true already tells the agent this is a safe read, so the burden is reduced. The description adds only the paging trait ("Paged"), which is also expressed in the schema's page/per_page fields; nothing is said about ordering defaults, empty-result behavior, or how much of the invoice body comes back.

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 the resource, the disambiguating parenthetical, the filter surface, and the paging note. No filler words to trim.

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 10 fully documented optional filters and annotations covering safety, the description is nearly sufficient. The only gap is that no output schema exists, so the shape of the returned invoice list is left implicit rather than briefly characterized.

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 is already documented in structured form. The description's filter recital (supplier, status, number, date range, note, tags) mirrors, but does not enrich, the schema; baseline 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?

States a specific verb (List) and resource (incoming invoices), and immediately disambiguates it as supplier-side Eingangsrechnungen, which separates it from billomat_list_invoices (outgoing) and billomat_get_incoming_invoice (single record) without opening a schema.

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 enumerated filters imply the contexts in which the tool is useful, but there is no explicit when-to-use/when-not statement nor any named alternative (e.g. use get_incoming_invoice for one record). Usage is inferable rather than stated.

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