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

Annotations already declare readOnly/idempotent/non-destructive, so the safety profile is covered. The description adds genuinely useful context the annotations cannot: the computation basis (5% of revalued capital), the confidence-tier behavior ('only verified is the legal figure'), and a 'Not legal advice' disclaimer. However, it doesn't say what happens when both input modes are supplied, or how confidence tiers other than 'verified' should be treated.

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 sentences with the legal basis front-loaded, then input modes, then the confidence caveat, then the disclaimer. Dense and telegraphic phrasing ('and/or price, purchaseYear and buildingYear (optional land price and works)') costs a little readability but no sentence is filler.

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 present, return values needn't be explained, and a read-only seven-parameter calculator is adequately covered by the stated input modes and confidence semantics. The remaining hole is the works/worksYear pairing and whether the two calculation modes can be combined in one call.

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 coverage is only 43%, so the description has to compensate, and it largely does: it names monthlyRent, price, purchaseYear, buildingYear, and implicitly landPrice and works, and it explains what each mode computes rather than just naming the field. Gaps remain for worksYear and worksAmount (grouped vaguely as 'works'), and it never states that all inputs are optional or how partial inputs are handled.

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 domain-specific resource: computes the Luxembourg legal rent ceiling as 5% of revalued invested capital, and does so in both directions (rent→implied capital, price/years→owner ceiling). This is clearly distinguishable in substance from siblings, though it never names an adjacent tool like calculate_rent_subsidy or analyze_lease to draw the boundary explicitly.

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?

Gives concrete call guidance: 'Give monthlyRent to see the capital a rent implies, and/or price, purchaseYear and buildingYear ... for the owner's ceiling.' That tells the agent which input mode produces which answer, plus the interpretive rule that only confidence 'verified' is legally meaningful. It stops short of stating when to prefer a sibling tool or when this tool is not applicable.

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