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

Annotations already declare readOnly, idempotent, openWorld, so the safety profile is covered. The description adds genuinely useful context beyond structured fields: the data sources (CBS, Kadaster) and the payment requirement (0.003 USDC via x402 or 2 credits). The only untold trait is failure behavior for invalid or missing postcodes.

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-loaded with what the tool returns, then scope, then audience, then cost and sources. Dense and largely waste-free, though the audience sentence ('Property valuation context for...') is the least load-bearing part and could be trimmed.

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 no output schema, the description usefully names the return fields (WOZ value, trend, per-year municipal sale prices vs national), and it covers cost and sourcing. Only the response structure/pagination details and invalid-input behavior are left out, which is a minor gap for a read-only lookup.

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% and both parameters are described there, so the schema already does the heavy lifting. The description reinforces that either a postcode or a CBS buurt code is accepted but adds no syntax, format, or default detail beyond the schema, so the baseline 3 is appropriate.

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?

Specific verb/resource: it states the exact data returned (WOZ neighbourhood value with trend, municipal vs national sale prices) and the accepted inputs (postcode or CBS buurt code). Clear enough that an agent knows what it fetches, but it never distinguishes itself from the overlapping nl_home_basic / nl_neighbourhood / nl_neighbourhood_summary siblings, so it falls short of a 5.

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 description names target audiences (real estate, mortgage, investment, relocation agents) but gives no explicit when-to-use or when-not conditions, no prerequisites, and no guidance on choosing it over a sibling like nl_neighbourhood_summary. Audience framing is not the same as usage guidance.

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