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

Annotations already declare readOnly, idempotent, non-destructive, closed-world behavior, so the description only needs to add domain caveats — and it does: the assessment is explicitly 'Orientatio only' and covers only self-occupied German houses. It also discloses the output shape (green/yellow/red/unknown with justification, plus a prefilled link), which is behaviorally useful even though an output schema exists.

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 German sentences are front-loaded and information-dense with no filler. The trailing English sentence largely duplicates the German text, which is a small redundancy but also aids cross-language agents.

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 12-parameter, zero-required, output-schema-bearing diagnostic tool, the description supplies the purpose, the output structure, the domain boundary (German, self-occupied, single/double/terraced) and the reliability caveat, while the schema (100% coverage) handles the inputs. Nothing an agent needs in order to decide to call it is missing.

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 description coverage is 100%, so the schema itself carries all parameter meaning (units, enums, the 55 °C flow-temperature test, the gas-advance-payment fallback). The description adds nothing about the 12 parameters, 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 ('Schätzt') and a precise resource/scope: readiness of a German owner-occupied single-family, semi-detached or terraced house for an air-water heat pump. It also enumerates the concrete outputs (traffic light, heating-load class, next step, prefilled link), so an agent knows exactly what comes back.

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?

'Orientation only' plus the reference to a 'vollständigen kostenlosen Check' makes clear this is a rough pre-assessment, not a full analysis. There are no sibling tools to route between, but there is no explicit statement of when the tool should not be used (e.g., non-residential, rented, non-German buildings).

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