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

Annotations already declare readOnlyHint=true and openWorldHint=true, covering the safety and non-exhaustive nature. The description adds valuable context beyond this: it names the underlying services (BORIS, ALKIS), notes the land value is 'geschätzt' (estimated), and explains that a complete address is needed for a unique match. This goes beyond the annotations and informs the agent about the data sources and the estimation aspect.

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 two sentences with no filler. The first sentence front-loads the core functionality and sources, while the second concisely states the input requirement. Every clause adds value, and the structure is efficient for an agent to parse quickly.

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?

There is no output schema, so the description carries the burden of explaining what the tool returns. It clearly enumerates the three outputs (official land value, parcel with area, estimated land value) and the data sources. It also explains the input requirement. While it doesn't detail the exact response format or error behavior, for a read-only open-world tool with no siblings, this is sufficient for an agent to understand what to expect.

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 provides descriptions and examples for all four parameters (100% coverage), so the baseline is 3. The description adds the key semantic that all parameters are jointly required to ensure an unambiguous hit, reinforcing the interdependency of the address components. This goes beyond the schema by explaining why each parameter is necessary.

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 clearly states the tool delivers official land value, parcel area, and estimated land value for a German address, specifying the exact data sources (BORIS and ALKIS). The verb 'Liefert' is specific, and the resource is well-defined, leaving no ambiguity about the tool's function. With no sibling tools to differentiate, this fully establishes purpose.

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 explicitly states that street, house number, postal code, and city are necessary for an unambiguous result, giving clear guidance on when the tool is appropriate. It does not mention alternative tools because there are none, but the requirement statement effectively tells the agent that a complete address is a precondition. This is clear context, though not an explicit 'when-not' clause.

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