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

Beyond the annotations, the description discloses the data source (Kadaster BAG via PDOK), the returned fields and distance, and the cost model including the free daily quota and x402/API-key payment options. These are material operational details an agent would otherwise have to discover at call time.

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?

The description is front-loaded with the use case and input, then compactly lists outputs, source, and cost. Every sentence carries information an invoking agent needs, including the free-tier detail that affects whether payment is required.

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?

There is no output schema, so the description appropriately enumerates the returned address components and nearby addresses. It also covers input CRS, data source, coverage area, and payment requirements, leaving no major gap for a two-parameter paid 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?

The schema already documents both parameters at 100% coverage, so the baseline is 3. The description adds meaningful meaning by specifying WGS84 as the coordinate system, which is not stated in the schema and matters for correct invocation.

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?

The description states a specific verb and resource ('reverse geocode Dutch coordinates' to 'nearest official BAG address') and names the exact outputs. It is clearly distinguishable from siblings like nl_postcode_addresses, which appears to go from postcode to addresses, and nl_address_lookup, which is not coordinate-based.

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?

It gives a clear use condition: coordinates in the Netherlands where an address is needed. It does not explicitly name when to use alternatives such as nl_address_batch for multiple points or nl_postcode_addresses for the reverse direction, 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.