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

Discloses what annotations cannot: exact price ($0.005/call), the x402 payment handshake (call unpaid to receive PaymentRequired, retry with _meta["x402/payment"]), a free preflight alternative, data provenance/license, and an explicit negative ('No confidence field'). This also explains why readOnlyHint=false despite a query-shaped operation — the call has a monetary side effect.

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 purpose, then output contract, then the payment mechanics that determine whether the call will fail. Slightly wasteful: '$0.005' appears twice and the HTTP-equivalent URL plus the base URL both restate the same endpoint identity.

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 supplies the return contract (status vocabulary, returned components, provenance, absence of confidence). It also covers cost, payment path, and a free preflight. What is missing is failure/error behavior and any rate limit on the paid endpoint.

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 100% and the nested address object is already documented as street_number/street_name/locality/postcode required with unit/street_type/state optional. The description adds only that the preflight takes 'the same body', with no extra format, normalization, or postcode rules.

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+resource: Netherlands address validation against BAG via PDOK Locatieserver, and names the outcome vocabulary (matched / partial / no_match). The 'nl' scope implicitly separates it from address_leg_us, address_bundle and address_verify, but it never explicitly contrasts with those siblings.

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 one concrete usage routing rule: a free pre-check endpoint to hit before spending money. It does not say when to choose this leg versus address_verify, address_bundle, or address_leg_us, leaving the agent to infer that routing from the tool name alone.

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