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

The readOnlyHint annotation is consistent with the read-only wording, and the description adds valuable behavioral context: results are scoped to the connected business and each row includes the open amount and overdue flag. Since there is no output schema, this output-oriented detail is especially useful.

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 sentences convey the tool's purpose, filter axes, output fields, and two concrete use cases without redundancy. The most important information is front-loaded, and every sentence earns its place.

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 search/list tool with no required parameters and a readOnly annotation, the description covers scope, filter dimensions, and key output fields. The missing output schema is compensated by the explicit note that each row carries the open amount and overdue flag.

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 the schema already documents all five parameters in detail. The description adds a useful conceptual grouping (status, time range, search term) and a practical example, but it does not provide material parameter-level meaning beyond the schema.

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 starts with a specific verb ('Listet') and a clear resource ('Rechnungen des verbundenen Betriebs') and immediately names the filter dimensions: status, time range, and search term. This makes the plural list/search intent unmistakable and distinguishes it from sibling tools like rechnung_lesen or offene_posten.

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 example questions ('welche Rechnungen sind noch offen?', 'was habe ich der Müller GmbH im Juli berechnet?') clearly illustrate when to use this tool. It does not explicitly mention when not to use it or contrast it with sibling tools, so it stops short of full routing guidance.

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