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

The description adds meaningful behavior beyond the annotations: the response is delivered in 'focus', and the function's behavior changes depending on whether no code, a regional key, or an IK is provided. The annotations already cover read-only and idempotent traits, so the additional hierarchical behavior is valuable and non-redundant.

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 focused sentences with no filler. The core purpose is front-loaded, and the second sentence adds the necessary hierarchical behavior without repeating schema details.

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, idempotent, two-parameter tool with an output schema, the description fully covers the invocation modes and the expected resource contents. There are no critical gaps for an agent to select and call the tool correctly.

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?

The schema already documents both parameters fully, so the baseline is 3. The description enriches the code parameter semantics by explaining that an IK returns the complete hospital record while a regional key returns the underlying directory level, and that an empty code returns the top-level Bundesländer.

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 uses a specific verb ('Liefert') and names the exact resource: complete hospital data including Name, Träger, Anschrift, Bundesland, Kreis, and contact details. It also distinguishes the tool's behavior from the sibling search tool by describing the hierarchical catalog levels.

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 clear invocation conditions: no code returns Bundesländer, a Bundesland or Kreis key returns the next lower level, and an IK returns hospital details. It does not explicitly name kh_search as the alternative for fuzzy or filtered lookups, so it stops short of explicit when-not guidance.

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