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

Annotations already declare readOnlyHint=true, so the safety profile is covered. The description adds valuable domain-behavior context beyond annotations: it explains that the tool returns a composition structure, that 49 € is already included in larger prices, that night/weekend/holiday rates are different, and that no VAT applies. It does not explain auth or rate limits, but for a read-only informational tool this is a rich disclosure.

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?

The description is front-loaded with a WHAT section, which helps, but it then becomes a dense jumble of return-value details, domain warnings, contact routing, and VAT notes. Some content, such as the return shape, duplicates what the output schema already provides. It is information-rich but not structured for quick consumption.

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?

Given the complexity of a price-composition system, the description covers what the tool returns, what it does not do, and which sibling tools to use for related tasks. Because an output schema exists, the description need not explain return values, yet it does so anyway, adding some redundancy. It is complete enough for correct invocation, with minor rough edges.

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%, and the single locale parameter is fully documented in the input schema with enum values, default behavior, and URL prefix details. The description does not mention the locale parameter at all, so it adds no meaning beyond the schema. Baseline 3 is therefore 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?

The description states that this tool returns the 'Official Festpreis matrix + composition SYSTEM' and clarifies it is to 'understand how to assemble a price.' It distinguishes itself from the sibling get_invoice_line_items by explicitly saying it 'DOES NOT compute one customer total.' However, the purpose is buried in dense jargon and all-caps labels rather than stated as a clean verb+resource, so it falls short of a perfect score.

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 gives explicit when-to-use guidance ('USE to understand how to assemble a price') and when-not-to-use guidance ('DOES NOT compute one customer total — that is get_invoice_line_items(situationKey, whenKey)'). It also names supporting tools for related tasks: compose_whatsapp/compose_mailto for contact and get_ort_datetime for whenKey. This is exactly the kind of routing information an agent needs.

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