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

Annotations already declare it a non-destructive, non-open-world read, and the description adds real behavioral depth: the estimate is derived from nearby comparables, `confidence` and `sample_size` encode trustworthiness, the point estimate is omitted when too few comparables back it, and the whole thing is a model output rather than an appraisal. These are failure-mode and reliability details the annotations cannot express.

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?

Three short paragraphs in a sensible order: what it does, how it sources and qualifies the estimate, then what is returned. Mostly front-loaded and tight, though the final sentence's 'no comparable listing is reproduced in it' is a borderline detail given the output schema already exists.

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 an output schema, annotations, and full parameter coverage, the description fills the remaining gap by explaining comparables sourcing, trust signals, and degenerate cases. It is nearly complete; only the relationship to the sibling retrieval tools is left implicit.

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 already documents all 11 inputs, including the subtle `rented` and `features` semantics. The description adds essentially no input-level meaning beyond that; its explanatory content (confidence, sample_size, point-estimate absence) concerns outputs, which the output schema covers. 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 and resource ('Estimate what a German address is worth to buy and to rent'), with explicit scope (Germany, both sale and rental valuation). It is clearly distinguishable from the sibling tools get_listing and search_listings, which retrieve existing listings rather than produce a valuation.

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?

'Works for any address, listed or not' implies you do not need a listing first, which is useful context against get_listing/search_listings, but the description never names those siblings or states when to prefer them. The only explicit directive is parameter-level ('Leave it out unless you know which it is' for `rented`), so usage is implied rather than spelled out.

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