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

Goes well beyond the annotations by disclosing the billing model (one trial address or credit per unique address), the free cases (same address within 7 days, answer without WOZ values, errors), and the auth requirement (trial_code unless signed in or an API key is configured). These are exactly the side-effect and prerequisite details an agent needs before calling a billed lookup.

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?

Front-loads the purpose, then packs cost model, usage restriction, and auth into three tight sentences with no filler. It is dense and slightly crammed, but every clause carries operational information an agent would otherwise have to guess at.

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 two-parameter lookup with no output schema, it covers purpose, return scope ('all available years, with the address as matched'), billing, caching, and authentication. Nothing an agent needs in order to invoke it correctly appears to be 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 both parameters are already documented, and the description's statement that a trial_code is needed adds auth context but largely echoes the schema's own note about trial_code and signed-in state. Per the baseline rule, 3 is appropriate when the schema carries the parameter detail.

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 ('Returns the WOZ values of one Dutch address for all available years') and immediately scopes it to a single address with the address as matched. This clearly separates it from sibling tools like get_address_list or start_trial, which are about lists, trials, and payments rather than a single property 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?

Explicit when-to-use and when-not-to-use: 'For questions about properties, not to assess or profile people', plus the cost/eligibility condition that one trial address or one credit is consumed. It does not name a sibling as an alternative for cases where the address is unknown (e.g. get_address_list), so it stops short of full routing guidance.

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