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

Annotations already cover the safety profile (readOnly, non-destructive, closed-world), and the description goes beyond them with two genuinely valuable disclosures: the Amazon link is an affiliate link ('Partnerlink, wird von uns erfasst') and price is returned only when freshly sourced from the Amazon API, otherwise only a price band. It does not say what happens when a calendar is not found.

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, front-loaded with the purpose and then a dense enumeration of return fields; every clause carries information. The field list is long but each item is a distinct returned attribute rather than 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 no output schema, the description carries the entire burden of describing return values and does so thoroughly, including conditional price behavior. It is only slightly incomplete on failure behavior for an unknown or ambiguous calendar name.

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% and the single parameter already documents both accepted forms (slug from find_calendars or name) with an example. The description adds nothing about the parameter, so the baseline 3 applies.

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 ('Liefert alle Details') and resource ('Adventskalender') and enumerates exactly which fields come back, so the agent knows this is the detail-retrieval tool rather than a search. It never explicitly contrasts itself with find_calendars or similar_calendars, which would have earned a 5.

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?

Usage is only implied: the agent can infer it should call this once it has a slug, and the schema's parameter text mentions 'Slug (aus find_calendars)', but that hint lives in the schema, not the description. There is no explicit when-to-use / when-not-to-use statement or named alternative.

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