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

Beyond the annotations (readOnlyHint=true, destructiveHint=false), the description discloses a significant behavioral detail: when the address is not released, street/house number are null and the coordinate is deterministically offset by 150-300 m with koordinaten_versetzt = true. This is exactly the kind of non-obvious behavior an agent needs to interpret results correctly.

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 compact and front-loaded with the core purpose, then lists the contained data fields, then explains the edge-case behavior, and finally documents parameters. Every sentence earnes its place with no wasted words.

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 adequately lists what an agent can expect in the response (prices, costs, areas, amenities, energy cert, texts, images, contact, URL). It also covers the address obfuscation edge case and provides the parameter source information needed to construct a valid call. The annotations already cover the read-only safety profile.

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?

Even though the JSON schema has no property descriptions, the description explains public_id as a hex identifier obtained from listings or the exposé URL, and specifies locale values with a default of en. This fully compensates for the schema's lack of param semantics and adds practical usage context.

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 opens with 'One GUTHMANN listing in detail' and enumerates the specific content included (prices, running costs, areas, amenities, energy certificate, exposé texts, images, contact, URL). This clearly distinguishes listing_details from the sibling listings tool, which presumably returns multiple listings.

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 indicates that public_id comes 'from listings or the exposé URL', giving a clear link to the sibling listings tool and how to obtain the identifier. It implies this tool is for fetching one listing's full detail rather than a list, though it does not explicitly list when-not-to-use alternatives.

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