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

Annotations already declare read-only, idempotent, non-destructive behavior, and the description adds real domain context: the tax is computed at each state's own rate, notary/registry fees come from the GNotKG table dated 1 June 2025, and loan/commission components are optional and user-supplied. That version date is useful behavioral disclosure beyond the annotations.

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?

A single dense sentence, front-loaded with the country marker and the main computation before the optional components. Efficient, though the parenthetical and version-date clauses make it slightly heavy for one sentence.

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?

No output schema exists, and the description explains what is computed but not the shape of the result (e.g. whether it returns a breakdown, totals, or per-component lines). For a calculator with four optional inputs, that leaves a modest gap an agent cannot resolve from structured fields alone.

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 parameters are already documented; baseline is 3. The description adds some framing ('at the rate of each of the 16 states', 'land charge for a loan', 'commission the user gives'), but no new syntax or constraints beyond the schema.

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 (computes) and resource (real estate transfer tax, notary and land registry fees) with explicit geographic scope (Germany, 16 states). The 'GERMANY.' prefix and the field list let an agent distinguish it from sibling calculators like purchase_costs_it or purchase_costs_es at a glance.

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 country-specific scope implies when to use it (buying a home in Germany), but there is no explicit when-to-use/when-not guidance and no named alternative. Given the large sibling set of country cost calculators, naming the alternative for other countries would have been useful.

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