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

Annotations already cover readOnly, idempotent and non-destructive, so the bar is lower; the description still adds real context: the 07:30-12:00 / 13:00-18:30 weekday availability, exclusion of holidays and company holidays, the three-week horizon, and that results also include services bookable by appointment vs. by quote.

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 availability scope and constraints are front-loaded in the first two sentences before the optional-filter note. The remaining text—brand history and the English restatement—is padding that does not help an agent decide or call, so this is the weakest part of an otherwise tight description.

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?

No output schema exists, and the description does step in to say the response includes both appointment-bookable and quote-only services, plus the bookable window and slot length. That is enough to call it correctly; only the exact result structure remains unspecified.

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% with explicit date-format and enum descriptions, so the schema does the heavy lifting. The sentence 'Optional nach Zeitraum und Tageszeit eingrenzen' only restates what von/bis/tageszeit already convey, adding no new syntax or constraint detail.

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 and resource ('Liefert die freien Termine'), plus concrete scope: 30-minute intake slots at Garage Kuhn AG in Thalwil. An agent can tell this is the availability-lookup tool as distinct from termin_buchen, though no sibling is named explicitly.

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?

Says the result can optionally be narrowed by time range and time of day, which implies when to pass filters, and gives a bookable window (tomorrow to three weeks out). It never says when not to use it or that booking should follow via termin_buchen, so routing is left to inference.

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